Speaking of Pizza tipping:
There's a pizza place near me that has a pretty good special. For lunch you get a 9 inch pizza + drink for $4.85.
So lets say you and someone walk in, order at the register and pay $9.70, receive your cups, get your own drinks from a fountain, sit down at a table, they bring you the pizzas, and then when you're done you just leave and they clean it up.
Do you leave a tip on the table?