Dear drunkards...

[Eye_Gore]

I think it's less likely that they honestly believe that intoxication improves their performance

If they are drunk enough to be slurring words, then yeah don't think they will perform too well, motor skills going a little too slow. ( unless its a DPS then they could be passed out and will still complete the instance) Though alcohol does effect people differently. Alcohol has some weird attributes. Its one of the few drugs if not the only one, that will act as a stimulant at first then change to a depressant with more consumption.