Most decisions don't require extensive research.

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.

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.

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

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

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.

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.

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.

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

Accept yourself and expect more from yourself.

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.

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.'

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.

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

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.

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.

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.

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.

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.

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

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.

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.

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.

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.