I'm going to leave my popcorn on the floor and my shopping cart in the middle of the lot and no amount of whining on the internet is going to keep you from having to do your job you so loathe to perform. I'm not going to tip you, you already get paid.
Don't bother trying to use "common courtesy" as an excuse. That's just what lazy workers say to try guilt the people they must serve into doing their job for them.