My good deeds are to never give homeless tweekers a smoke, so they don't get lung cancer, and never give them money so they can't buy drugs that are bad for them.
I also pour old hot sauce, ketchup, or whatever on my recyclables to discourage them from scavenging thru my trash.
I zip tie shopping carts to people's cars to teach them to park correctly. And if a person can't make the effort to put their shopping cart in the corral, I put it behind their car, so this motivates them to put it away properly, and gives them exercise.
Sometimes I run into people's car doors and mirrors to teach them how to look before turning into a parking lot.
I bump into people that are staring at their phones while shopping, to raise their awareness of things around them.
I love to have conversations with dogs that are barking at me. "Fuck you too!" Their owners love that.