A friend of mine used to waitress in NY and she always claims that the worst customers ever are groups of young women and the best customers are groups of men (any age).And then I'll project my bug-bear - which is people who itemize bills. Okay, so if you're going dutch just split it down the middle. Don't itemize who had the steak compared to the salad, the whiskey compared to water, dessert and coffee afterwards or not... whatever... that kind of thing makes my head explode. Just go half and don't keep tabs. If you're hanging with people who would take advantage of this, then consider why you're choosing to be around them.
The women will ask for the bill and then out comes the calculator on their phones and everything is calculated to the last cent.
The men will get the bill, add the tip and then round it up to the nearest figure easily divided by the number of men in the group.
I’m sure she was exaggerating but I have heard restaurant staff saying that they hate serving a group of young women because they tip so poorly.