Serious Eats - seriouseats.com

Re: free drinks: i worked at a high-end martini bar, and drinks that we as employees would buy would be 50% off up to a point, and we'd get a drink for ourselves at the end of the night anyway. i'd occasionally count my "shift drink" as one i "bought" for a customer. note that the one time i did this for customers, they were [EXPLETIVE] and extremely ungrateful, so i never did that again. way to ruin it for everyone else...

anyway. our regular customers were fantastic, but at times overstayed their welcome. so. don't just assume that because you tipped $50 on a $70 tab the night before that your bartender will just let it go when you "forget" your wallet.

since i worked in food service, i have left a bad tip ONCE. i felt terrible about leaving 10%, but he wasn't even worth THAT much. my usual is 20% for average service.