I like caffeine so much that I know I would like nicotine, even though I’ve never had it. That’s why I can never try it.
This last week I cut my caffeine intake by about four-fifths (my former intake was 1 cup of strong coffee and 1 coke, supplemented some days by another cup or iced tea). It was painful, but worth it. The way my mind works, somewhat nervous and anxious already, does not need additional stimulation. God gave me my own internal caffeine that should not be enhanced.
Caffeine, I read, increases stress hormones among its effects. Now, I find myself doing more to actually address sources of stress than feeling stress itself. And fewer stress hormones also means better control over the appetite, which is stimulated by cortisol, adrenaline, and the like.
If you have a nervous or anxious personality, try to cut down the caffeine and see how you feel.