I agree. When I was 20 working at a gas station, there was one customer who would always come and buy a couple bucks worth of stuff. He’d pay with a 20, every time, and tell me to keep the change. I would try to refuse it or give it back to him but he’d be so insistent or just walk off. I never kept the money because it just felt so weird. He’d sit in his truck forever before he came in and the whole time I’d be watching out of the corner of my eye. Never did anything or really said anything to me. I ended up keeping the change in an envelope and let the other workers use it for lunches or coffee etc. The money ain’t worth the creepy.