I used to have major issues with coffee during my graphic design class days. For some reason, too much caffine makes me violent. I mean, I can CONTROL it, but if I have say 4 coffees in the space of an hour or 2, it agitates me to the point I can't be around people and I have to be very careful not to punch walls. It's not a fun feeling which is why I limit my coffee intake to maybe 3 a day max. It raises your heart rate which isn't healthy for you.