Because a server makes about $2 an hour and the restaurant requires you to tip in order to have them make a livable wage. I think we should move away from it but if you go to a restaurant that supports tipping then you should tip. Tip more for great service but tipping nothing or next to nothing is just scummy behavior regardless of service.
So do you think there should be a minimum that should be tipped or are you okay leaving a measly amount if they don’t pass your arbitrary standards?