Most people understand the concepts of courtesy, respect, and dignity. Even rude people know how to be respectful when they want something !! Competent people are courteous and respectful, and try to avoid rudeness. This requires a decision.
You can DECIDE to treat other people with courtesy and respect
‘An older man stopped to hold a door for a young woman. The woman told the man she was perfectly capable of opening the door herself, and that it was patronizing and sexist for him to hold the door for her just because she was a woman. He said “Madam, I did not hold the door for you because you are a woman. I held the door for you because I… am a gentleman.’
Even when other people are rude to you, try to remain courteous. This is a simple test of self control and self confidence, and rudeness is not cured with more rudeness. Remember your manners !!