Self-knowledge makes me happy.

Relationships make me happy.

Creativity arises from a constant churn of ideas, and one of the easiest ways to encourage that fertile froth is to keep your mind engaged with your project. When you work regularly, inspiration strikes regularly.

No one regrets having changed a lightbulb.

Feelings follow actions. If I'm feeling low, I deliberately act cheery, and I find myself actually feeling happier. If I'm feeling angry at someone, I do something thoughtful for her and my feelings toward her soften. This strategy is uncannily effective.

Your unhappiness doesn't help anyone else - and in fact, as I mentioned in another answer, happy people are more altruistically inclined. So happiness is not a selfish goal.

Pouring out ideas is better for creativity than doling them out by the teaspoon.