I can't speak to his business skills, but I can attest that he never once offered a tip for his daily black iced tea. We'd even have it ready for him before he showed up so he never had to wait! He would pay with cash, and I'd hand him his change and drink, and that was that.
It's funny to me now: one of the richest men in the world and he never once offered a tip.
Frugality aside, he was always very polite and warm so I can't be mad. Makes for a good ice breaker story.
Edit: holy moly, this is a sensitive subject. Please remember this was from a time before tipflation. Tipping meant you left your change behind once in a while only if you felt the desire to show appreciation. It wasn't an obligation. Yes, I still do think it's a funny story. Roast me for being entitled lol