It's very easy to take too much caffiene. It can make you restless, very irritable (not something I care to be like at a track with friends around me) and not in a good mood.
I know that when i'm racing, it's got to be fun
You can't do that well if you're too pumped up on caffiene.
There's a lot of different stuff to r/c out there that makes it the hobby it is when you put your mind to it........