My dad never returns carts. He also worked at a grocery store when he was young and had the same mentality as this. He also said that he is "creating work" for these young kids and it's good for them ha.
Personally, I return carts - because when I worked in a service job, I always had more "important" things to do than clean up after slob customers.
I liked getting carts too, but I return mine, because no one else I worked with liked doing it. I’m not going to force someone to do work they might not want to do. I don’t know them, and statistically (from my n of probably 50), most people don’t want to do it… especially in the winter.
Most of the time I will leave my cart inside and carry my bags to the car. I use the small carts and they run out a lot, so I like to leave it there for other people who like the small carts.
Personally, I return carts - because when I worked in a service job, I always had more "important" things to do than clean up after slob customers.