I don't usually get into contact with caffeine.
However there was a time when I would drink it every morning as a way to get out of bed at all: I would prepare some black tea the night before and place it next to my bed. Then when the bell would ring I would get up as fast as possible, drink my cup of black tea and go back to sleep until the caffeine activates.
I do realize that this is not the best way to take caffeine, but I used it as a way to "energize" myself. Not anymore however, because I don't want to depend on it since addiciton isn't all that great.
When I take caffeine and it's not regularly I get all the usual effects very intensely like faster heart beat, racing thoughts, but less accurate thaoughts, shallow wakefulness... etc.
I don't often drink coffee at family gatherings, but one time I did and kinda owned the place, I was so outgoing, lol.
I wouldn't recommend to make it a habit though because it's like any other drug, you need more and get withdrawal symptoms after a while.

That's interesting. I very rarely get racing thoughts, occasionally I get anxious- but that's usually only when I haven't eaten. If I haven't slept well coffee helps me get through the day, but I generally feel worse. Haha, coffee makes me very peppy and happy, so I usually become more outgoing. I try to limit usage just so I don't become too dependent on it, and If I am already having a decent day I don't drink it- plus, it can be mildly expensive to maintain if you do lattes or some such.