Except that a restaurant is a very different experience from a store. Its not like you go into a store, pick out what you are going to buy, then take an hour to buy it.
Another vote to expect to be there at least an hour after you stop seating people.
Another vote to expect to be there at least an hour after you stop seating people.

They proceeded to sit at the table chatting, no problem as it wasn't a particularly busy night. We closed at 8:00, but a table of 7 had come in 2-minutes before 8:00 *grumble grumble grumble* so we waited until 8:30 to start cleaning up. When I started the vacuum in the entryway, the couple said "uh oh, we better get out of here, they're closing" and I smiled and said good-bye to them as they walked out. The other waitress came over to me and said the guy had left me $4 more for "taking up the table so long." I thought that was so sweet of him, and I ran out the door and caught him and said thank you. Not many people do that, so it was a nice surprise!