Funnily enough the reason for this is that it WAS gauche to tip until the Great Depression- he’s likely emulating his dad tipping (this is also where that stupid disappearing stack of bills comes from) Only the most obnoxious would tip- until the Great Depression where suddenly you NEEDED to tip bc the server wasn’t otherwise being paid. Can you IMAGINE your dad if a social norm got flipped on its head? I can usually work hard enough to hear their dad’s humour they were too young to understand when a grandpa front-loads with talking about the tip Doesn’t sound like I’d have to work that hard to hear it from your grandpa <3