I'm a good tipper, but my wife will even give me the side-eye if I only tip 25%. She's pretty fucking free with my money.
I also gave the boy the speech about "not today, I know you're a poor student with no money, but once you start working, and you go to a bar to actually sit at the bar with a date, friends, whatever....tip nicely right at the start of the night. Talk to the bartender, tell him/her 'I appreciate you taking good care of me tonight,' and slip them a 20 at the beginning of the night." Doesn't have to be visible to anyone else, it's about having a rapport with the bartender, and being treated well and engaging with them. The visibility is "huh, the bartender seems to think this guy is a great dude, I guess I should too." If you go someplace frequently, and can do it with a regular bartender, even better.
At present, he's still bitching about spending 3 pounds on a pint of shitty Tennents, but he'll get there.