I tip if they deserve it and most places i go people do deserve it.
I went for a burger the week day at this diner place in London, it took a life time to order because the staff were just chatting. I then finally ordered a burger, medium rare, but it came crispy on the outside a raw in the centre, it wasn't even warm on the inside. The waitress said, "that's what medium rare looks like". I said "well what the hell does rare look like? Do you just bring me a live cow?" She wasn't impressed and huffed as she walked away, then she actually just chucked the plate down on the table!
When the bill came it said that their service charge had already been added to the bill, i asked if there was any way to take this off because if i pay £9 for a burger i expect it cooked how i want to and i don't expect to be told i'm wrong, when i was quite clearly right.
Anyway, my point is most people do deserve to get tipped, the tight asses who don't tip anyone are dicks and to say the reason why you don't is because you only give god 10% so why should you get more?? I think people have religion backwards, aren't we meant to love each other?
God would have tipped.......
(I've put this in a spoiler because i don't want to offend people, so if you open it and get offend it's your own fault)