I have something of a rule re friends - if I see them doing something I would simply never, ever do (for ethical reasons) then whether it's a small thing or a b

I have something of a rule re friends - if I see them doing something I would simply never, ever do (for ethical reasons) then whether it's a small thing or a big one; I end the friendship. I know a much bigger ethical lapse will be coming. When I've bent this rule, as I did for one fellow I liked a lot who tossed his butts wherever, I found out a couple of years later that I'd have been much better off dropping him out of my life the first time he tossed a butt.