The days are long, but the years are short.

One of the best ways to make yourself happy in the present is to recall happy times from the past. Photos are a great memory-prompt, and because we tend to take photos of happy occasions, they weight our memories to the good.

Being taken for granted is an unpleasant but sincere form of praise. Ironically, the more reliable you are, and the less you complain, the more likely you are to be taken for granted.

Don't let the perfect be the enemy of the good. Lower the bar. Actually spending ten minutes clearing off one shelf is better than fantasizing about spending a weekend cleaning out the basement.

Negative emotions like loneliness, envy, and guilt have an important role to play in a happy life; they're big, flashing signs that something needs to change.

Turn off your email; turn off your phone; disconnect from the Internet; figure out a way to set limits so you can concentrate when you need to, and disengage when you need to. Technology is a good servant but a bad master.

Nature is impersonal, awe-inspiring, elegant, eternal. It's geometrically perfect. It's tiny and gigantic. You can travel far to be in a beautiful natural setting, or you can observe it in your backyard - or, in my case, in the trees lining New York City sidewalks, or in the clouds above skyscrapers.

A 'treat' is different from a 'reward,' which must be justified or earned. A treat is a small pleasure or indulgence that we give to ourselves just because we want it. Treats give us greater vitality, which boosts self-control, which helps us maintain our healthy habits.

We need to have intimate, enduring bonds; we need to be able to confide; we need to feel that we belong; we need to be able to get support, and just as important for happiness, to give support. We need many kinds of relationships; for one thing, we need friends.

Often, if there's something that I want to do, but somehow can't get myself to do, it's because I don't have clarity. This lack of clarity often arises from a feeling of ambivalence - I want to do something, but I don't want to do it; or I want one thing, but I also want something else that conflicts with it.

Working is one of the most dangerous forms of procrastination.

Getting paperwork under control makes me feel more in control of my life generally.

I'm a compulsive note-taker, and I used to feel self-conscious about pulling out my little notebook and taking notes during a casual conversation. Then I noticed that people really seemed to enjoy it; the fact that I was taking notes made their remarks seem particularly insightful or valuable. Now I don't hold myself back.

I have a lucky perfume. I love beautiful smells, but I save one of my favorite perfumes to wear only when I feel like I need some extra luck.

Enthusiasm is a form of social courage.

Skillful conversationalists can explore disagreements and make points in ways that feel constructive and positive rather than combative or corrective.

While television is a good servant, it's a bad master. It can swallow up huge quantities of our lives without much happiness bang for the buck.

A person with 'oppositional conversational style' is a person who, in conversation, disagrees with and corrects whatever you say. He or she may do this in a friendly way, or a belligerent way, but this person frames remarks in opposition to whatever you venture.

In the scope of a happy life, a messy desk or an overstuffed coat closet is a trivial thing, yet I find - and I hear from other people that they agree - that getting rid of clutter gives a disproportionate boost to happiness.

I'd always vaguely expected to outgrow my limitations. One day, I'd stop twisting my hair, and wearing running shoes all the time, and eating exactly the same food every day. I'd remember my friends' birthdays, I'd learn Photoshop, I wouldn't let my daughter watch TV during breakfast. I'd read Shakespeare.

If you've had something for more than six months, and it's still not repaired, it's clutter.

As goofy as it sounds, I try to sing in the morning. It's hard both to sing and to maintain a grouchy mood, and it sets a happy tone for everyone - particularly in my case, because I'm tone deaf, and my audience finds my singing a source of great hilarity.

Some kind of clutter is difficult - letting go of things with sentimental value, sifting through papers - but some clutter I find very refreshing to clear. I drive my daughters nuts because I'm always wandering into their rooms to clear clutter.

One major challenge within happiness is loneliness. The more I've learned about happiness, the more I've come to believe that loneliness is a terrible, common, and important obstacle to consider.

Many people keep photos in their homes, in their office, or in their wallet, and happy families tend to display large numbers of photos at home. In 'Happier at Home,' I write about my 'shrine to my family' made of photographs.

No leader did more for his country than Winston Churchill. Brave, magnanimous, traditional, he was like a king-general from Britain's heroic past. His gigantic qualities set him apart from ordinary humanity; there seemed no danger he feared, no effort too great for his limitless energies.

The more I examine the issue of clutter, the more effort I put into combating it, because it really does act as a weight.

When we're trying to form and keep habits, we often search - even unconsciously - for loopholes. We look for justifications that will excuse us from keeping this particular habit in this particular situation.

Each week, I post a video about some 'Pigeon of Discontent' raised by a reader. Because, as much as we try to find the 'Bluebird of Happiness,' we're also plagued by those small but pesky 'Pigeons of Discontent.'

If I can do something in less than one minute, I don't let myself procrastinate. I hang up my coat, put newspapers in the recycling, scan and toss a letter. Ever since I wrote about this rule in 'The Happiness Project,' I've been amazed by how many people have told me that it has made a huge difference in their lives.

Accept yourself and expect more from yourself.

One of my 'Secrets of Adulthood' is: Somewhere, keep an empty shelf. I know where my empty shelf is, and I treasure it.

If you're impatient while waiting for the bus, tell yourself you're doing 'Bus waiting meditation.' If you're standing in a slow line at the drugstore, you're doing 'Waiting in line meditation.' Just saying these words makes me feel very spiritual and high-minded and wise.

During my study of happiness, I noticed something that surprised me: I often learn more from one person's highly idiosyncratic experiences than I do from sources that detail universal principles or cite up-to-date studies.

Putting myself into categories is fun, and I think it also gives me insight into my own nature. When I see myself more clearly, I can more easily see ways that I might do things differently, to make myself happier. Categories can be unhelpful, however, when they become too all-defining, or when they become an excuse.

I love taxonomies, categories, ways of dividing people into groups.

Remember that although the distinction can be difficult to draw, loneliness and solitude are different.

I have a terrible memory of my own past. I can barely remember my childhood. I have few memories from college and law school - though once I got married, I got the advantage of being able to consult my husband's memory.

Habit allows us to go from 'before' to 'after,' to make life easier and better. Habit is notorious - and rightly so - for its ability to direct our actions, even against our will; but by mindfully shaping our habits, we can harness the power of mindlessness as a sweeping force for serenity, energy, and growth.

Most decisions don't require extensive research.

Most people enjoy 'potato-chip news' from time to time - to track a presidential election or the Oscars. However, some are particularly drawn to material that makes them feel shocked, frightened, insecure, or indignant, and that's what potato-chip news often provides.

Growing up in Kansas City, I was always neat, the teacher's pet, know-it-all type.

One thing I wish I could tell my younger self: take photos of everyday life, not special occasions; later, that's what will be interesting to you.

People often assume that the same approach will work for everyone, that the same habits will work for everyone, and that everyone has the same aptitude and appetite for forming habits, but from my observation, that's not true.

Sometimes, counter-intuitively, it's easier to make a major change than a minor change. When a habit is changing very gradually, we may lose interest, give way under stress, or dismiss the change as insignificant. There's an excitement and an energy that comes from a big transformation, and that helps to create a habit.

For one person, organized files might be a crucial tool for creativity; another person finds inspiration in random juxtapositions.

Kennedy was president for only 1,037 days, but during his short tenure, he achieved much. At the Cold War's most dangerous hour, he preserved the peace. He improved relations with the Soviet Union and replaced tension over Berlin with a limited test ban treaty.

We can use decision-making to choose the habits we want to form, use willpower to get the habit started, then - and this is the best part - we can allow the extraordinary power of habit to take over. At that point, we're free from the need to decide and the need to use willpower.

Whenever I'm trying to decide how to spend my precious time, energy, or money, I ask myself a series of questions. 'Will this broaden or deepen my relationships?' 'Will this contribute to an atmosphere of growth in my life?' 'Is this a way to 'Be Gretchen?' and 'Will this help connect me to my past?'

Like most people, I have several pet subjects - that may or may not be interesting to other people. Don't get me started on happiness, or habits, or children's literature, or Winston Churchill, unless you really want to talk about it.