For starters, the very job title describes how tough a waiter's job is. Someone who 'waits on people'. It can be tiring and annoying and frustrating and, for the peanuts that they get paid, they show a great deal of patience while putting up with all the shit customers give them.
In spite of all the trouble they go through, be it with rude customers or a hectic schedule, they don't give up. Very, very commendable!
If somebody says "Aye chotu, chai la" to you, you would probably boil with anger. But guess who deals with such customers on a regular basis and still manages to hold back a punch?