Back in the early 90s we thought that in order to impress a number of scouts (that's record company ones, not boys in shorts) we'd need to be uninhibited and exciting on stage. Which of course meant about 6 pints and a noseful of coke each.
We played abysmally... We never saw any scouts again!
But saying that, in the same band we'd always have some weed at rehearsals and gigs (actually, weed wasn't that available - it tended to be more of the soapbar solid variety which meant it wasn't usually very strong compared to the skunk available nowadays!). And we played well - our live recording in our living room still sounds OK now! (If you want a laugh! )
However, I have a max of 1 beer (*) before playing now, and haven't smoked any dope in decades!
*that's often due to driving though - recent gig in Chester saw at least 2 pints and a good glug of tequila before playing as the hotel was only 100m away! No decent cock-ups either...