This. This this this. I drive and cycle and I hate it when drivers try to surrender their right of way to me. Other road users aren't going to know about it and I am putting lives in danger if I accept their offer.
The absolute best thing you can do, regardless of mode of transportation, is to be where you are expected to be when you are expected to be there. Bending the rules is how people die.
My car broke down one night after dropping a friend off at his place.
I was about ten miles from home in a very hilly area.
A guy in a car around my size pulled over, pulled out a tow strap, and carefully got me home, even though the strap came off every other turn or so.
I tipped him with the rest of the meager cash I has.
A few weeks later he dropped by and asked me to sign up for his pyramid scheme. But the nice driver part was days earlier, I don't hold that against him.
I live in northern Minnesota. We understand that if someone is on the side of the road - especially in winter - that can be a crisis.
I have never been roadside in Minnesota while waiting for a tow truck without multiple people stopping to see if I'm okay.
We look after each other, but this was an exceptional story.
Also had a guy find me with a flat who had an air tank in his car, but it was empty. So he took us with him to get air and then filled my tire up and stayed with me and my wife until he was sure it was properly filled. Wasn't even winter, just cold and rainy.
Traffic is not really the place to be kind. Just don't be a dick and drive predictably and by the rules. Doing stuff like waving someone to go first when you have the right of way is dangerous and confusing.
That being said, one type of act of kindness that comes to mind is a semi using their blinker to indicate when it's safe to overtake as I couldn't see in front of them.
There's a huge difference between nice but also thoughtless and kind and thoughtful. Being predicable on the road is kind and thoughtful. Waving someone to go out of turn is nice but thoughtless