To not tip delivery people (At least in the U.S.) kills them. If they don't get tipped, they really don't make much money. Same with waitresses. My mom was once a waitress and a few other people I know.. their pay was such crap that without tips, they wouldn't have been able to pay for much xD

Yeah, my sister was a waitress at IHOP and she only made $2/hour so she made money of tipped.