One time, I drank like 5 beers, and then drank a bunch of Jack Daniels.
It was pretty fun, except for the puking, and then all the headaches. I stick with the natural stuff now.
I've only betrayed it once, but it was only a mixed drink at a restaurant and then a beer a few hours later. No worries.
At any rate, I found my drinking limit. I think this is the closest I've ever come to a hangover, though. I guess I'm one of those lucky ones.