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.
Gretchen RubinWhat I've also noticed is the term happiness, or happy is intimidating to some people. Some people deny that it's even possible to be happy, or to achieve happiness. Happiness sounds like this magical destination that you arrive at and then everything is sort of solved, or it's different.
Gretchen RubinGet enough exercise and sleep: Sounds trivial, but it's not. You may have the urge to work 24/7, to skip the gym and to stay up late to get a few more things done. That's short-sighted. Exercise and sleep are critical to having the physical and mental energy necessary to meet a challenge.
Gretchen RubinSometimes, 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.
Gretchen Rubin