I’ve been going to the same barber once a month for the past 15 years for a simple haircut that cost me $35, and I’d give him a $5 tip. Apparently, at some point over the years—I have no idea when—the barbershop’s rate for a haircut went up to $40 and he never bothered to tell me. Then last week I spotted a rate board by the cashier I’d never noticed before that clearly stated haircuts were $40. I was horrified when I realized I’d been stiffing my barber of his tip and had no idea how long I’d been doing so. I’m too embarrassed to ask him when the barbershop raised its rates and why he didn’t tell me. I do want to offer him a serious token of appreciation. What do I do?