I believe that karma is a useful concept that describes a real phenomenon.
In the real world, it matters how people behave. Behavior is catching. If people all start behaving in a good way, it encourages others to do the same. This is the “tipping point” concept. It’s why police are concerned with petty crime, like littering. If you start everyone into the habit of cleaning up, it actually reduced the serious crime rate once you’ve hit the tipping point.
So I believe that if I’m polite to someone who wants needs to turn into my lane, or if I give someone a helping hand, it encourages others to be polite while driving to help people out when they need it.
It’s about social politeness and it works. People tend to follow each other and are certainly influenced by each other. We can affect others in this way. What goes around, comes around. In real life. If we put positive energy out into the world, it grows and it comes back to us. If we put negative energy out there, then things get worse, and that comes back to us.
It’s karma.