I got a Groupon for a local coffee place, and I went in -- met the owner, bought enough coffee to use up the Groupon, and a few pieces of hardware so he probably made a tidy profit.
But while I was there, he offered me a cup of coffee on the house. I wavered, but accepted.
Caffeine doesn't do much for me. On an empty stomach it will make me jittery. Sometimes it affects my digestion. If I'm tired it will put me to sleep, knock me right out. But I've never had it behave in the manner that "normal" people say coffee does.