I like self checkouts personally, they do cut down on lines in my experience. You just have to take a little extra time and not be in a hurry. Most of those POS machines seem to be slow and you have to give them a bit of time to register your item. My big complaint, especially at walmart, is the small bagging area. Most people seem to think they are "professional" cashiers and screw it up by going to fast. Also make sure to have some hand sanitizer, those scanners have a lot of germs and likely haven't been cleaned all day.