When you are helping a customer, bad descriptor of someone shopping in your store (should be called a guest), they should be your focus and yes they are always right. That is service. Even if you don't agree they are always right. Learn better guest service and you will grow in your career don't and you will stay where you are complaining about the people that give you a job.
Bad mouthing the people that frequent your store and spend money in your store is not a way to keep a job or to keep people shopping at your store. Keep this type of behavior up employees of wal mart and you will no longer have a job. At least this is what I hope happens but knowing wal mart you will be just fine being rude and disrespectful because that is how your entire corporation is.
This is expected when you hire people of lower class and expect them to get better but do not help them or give them the ability to do better. Hire better people, pay your employees more, and have better service. Main things wal mart needs to do to become a better company more receptive to what their patrons/employees want, need, and desire.