Why do service counters , clerks, etc treat foreigners nicely, but treat citizens & normal people like garbage

For example, at the post office, they scowl and yell at me if i have a question or if i put the address one millimeter too low on the label.
But they will smile and exhibit heroic patience and spend 20 minutes helping the annoying foreigners who hand the postal clerks a pile of junk and an empty box and expect the clerk to do everything for them.
It's the same way at grocery stores, DMV offices, everywhere.
This is why people are getting angry, and are pist off at corporations and our government offices.

just do the same.
start with no habla senior....

I have never experienced that .. I would ask the clerk.

I have found that to be true, also. Maybe because their boss told them to be especially nice or they may get YOUR job?
hmmm.......

People feel a natural inclination to help the helpless. When foreigners are noce and ask questions, it makes workers feel important and useful, thus they are more helpful and accomodating. When we citizens deal with them, we are rude, act like we know it all and get annoyed with the workers, causing them to be rude to us. Be nice to them and they will be nice to you. If you really have an issue, ask the worker: "Did I do something to offend you?" and that should let them know that if the rudeness persists, you will call their supervisor.