The Angels tell us that being kind is the way to make sure that you accept someone or to accept a situation. Remember that the person who is abrupt or rude may have just lost a loved one. Or, perhaps they have found out that they have a major illness. And, yes, some people are just rude.
You do not have to be rude as a response. Simply be kind. If you do behave as they do, then that action will come back on you, as well. It is easy to give everyone the benefit of kindness.