I hate self check out and what it's become.
It should be the '10 items or fewer' line. Not, a full cart. If you can't carry the items in a basket, you need to go in a regular line.
My local grocery store has like 9 self check outs, with 1 person sometimes staffed to fix them when they fail (not if, when) and they have 1 regular lane open. And everything ends up with a long line and it's infuriating. Oh and the manger standing in the back 'monitoring things' acting like they're doing anything, but isn't doing the right thing and opening up a new lane.
Also, far too many people are over leaving into 'im an introvert' and playing it up to poorly written teen sitcom levels.