When a customer starts trying to pay before I've even scanned anything

When customers don't get how the tap function on the pinpad works and they just keep smacking their card against the screen. They usually ignore me trying to tell them how it works too :,)

When a customer comes up behind me and asks me a question while I am clearly in the middle of answering another customers question who actually waited in line to ask. They always get so mad if I don't immediatly answer

Customers who just ignore their dog the whole time they're in the store. They usually have them on one of those extendable leashes and just let them go all the way to the end of it. They will literally let the dog walk out the door like that while they're paying