I was at our bank a few weeks ago waiting in line. An employee walked out, obviously upset. He then proceeded to cuss under his breath about the customers and a fellow employee and then ask for the next customer he could help.
Most people didn’t hear him, but I did. If you are so unhappy about your job that you’ll cuss about customers in front of customers you don’t need to be there. You aren’t doing anyone any favors. Just quit. Find something you love and do it. Everyone will be happier if you do.