Ok here goes. I can tell that this thread will become my new hobby!

"Sorry I'm watching my weight - do you KNOW how many calories that wine/beer/whatever has?!" *insert horrified look*

"Actually I'm on a detox diet at the moment - you should really try it sometime"

"Sure - have you got any Cristal? That's all I drink these days"

"Just a lemonade for me - alchohol is against my religion"

"No, thanks - I've already puked 3 times tonight!" (slurring words, holding up 4 fingers!)