Why does coffee make me so happy?

I've been pondering this question for the last few years, ever since I started drinking the wonderful hot elixir derived from the "grano de café." (That's "coffee bean" in Spanish. It seems like coffee beans are almost always grown in Spanish-speaking countries, so I broke out the Español there because it sounded cooler.)

Drinking coffee makes me happy. The actual physical act of ingesting it warms my heart, both literally and figuratively. But why? Why is that? What is it about coffee that I love so much?

I have three theories:

(1) It comforts me

I know the caffeine in coffee is supposed to rev you up and give you energy, but it actually seems to have the opposite effect on me. Coffee makes me feel relaxed and content, much like alcohol does for many people. I drink a cup and I just feel...<insert relaxed sigh here>

(2) It tastes and smells SO DARN GOOD

I've mentioned before that this is the part that baffles me. Ten years ago, the taste of coffee repelled me. Now? Much like wine, I suddenly love it. I can't explain the switch, but I love it. I take mine with two tablespoons of half-and-half. And I never, ever get tired of the scent or the flavor.

(3) It keeps me from eating so much
As chronicled in this blog ad nauseum, I try to eat well and maintain some semblance of a healthy weight. Coffee, relatively low in calories even with the creamer I add to it, keeps me feeling full, and therefore presumably deters cravings I might otherwise indulge with sweets, processed junk and all manner of culinary nastiness.

Oh coffee, you do so much for me. How can I ever repay you? By drinking you, that's how. I will show my appreciation by continuing to drink you in mass quantities.