2 more to add:
When paying your tab, don't expect your server to make change/swipe your card at the snap of your fingers. I was very busy yesterday and someone gave me 2-$20's and I had to make change from the bar. I picked up the check, walked immediately over to the bar, asked for change, went back to the computer (right by her booth) to close out the check to put it in the check presenter, and I heard her say in a rude voice "Can I get my change." Not even 20 seconds had passed. I followed with "Yes, I'm waiting for change from the bar." Even for cards, sometimes there's a wait for the computer. Or sometimes we have to get out condiments for a table that just got their food. Or whatever. You'd be surprised at some impatient people get.
If you're in a hurry, a busy restaurant is not the place you want to go for lunch/dinner. If you are going to dine in when you're kinda in a rush, know what you want to order when you sit down. And don't order food that takes a long time to cook (rack of ribs, well done burger or steak, stuff like that) I've had so many people take 20 minutes to order, then right before their food came said "Hey, I'm in a hurry, where's my food?" Or have a movie to get to, but don't tell the server until 1-2 minutes before they have to get out. If you're on a time constraint, let your server know at the beginning.