Too much caffeine will leave you feeling like the world is just a little bit slower. Also, you feel loopy, laughter is extremely contagious, super bubbly, and a touch of euphoria.
I did that a few times in high school, typically once a week or every other week.
Usually, I'd make 4 double-shots of espresso to start the morning (served various ways, typically one big coffee cup with chocolate syrup and a little milk). Around lunch time, me and a few of my buddies that were also in the CCNA program (which lasted the second half of the day, after lunch) would then down one of those massive Monster cans.
Needless to say, it was quite.. interesting. I was quite literally high on caffeine. And it was awesome. :biggrin: