People are powerfully moved by imagination, belief, and knowledge. They can consider the past and future. They can make changes in their behavior out of reason, in a way that animals can’t do.

One reason that challenge brings happiness is that it allows you to expand your self - definition. You become larger. Suddenly you can do yoga or make homemade beer or speak a decent amount of Spanish. Research shows that the more elements make up your identity, the less threatening it is when any one element is threatened.

We’ve all heard of Dr. Elisabeth Kubler-Ross’ five stages of grief: denial, anger, bargaining, depression, and acceptance. In contrast, I realized, happiness has four stages. To eke out the most happiness from an experience we must: anticipate it, savor it as it unfolds, express happiness, and recall a happy memory.

Relationships make me happy.

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.

We are happy when we are growing.

Getting control of stuff makes people feel like they have more control over their lives - maybe irrationally, but it's one of these psychological truths.