I truly believe that when you are polite to people, they are more inclined to be polite back to you. If you approach a situation with a negative attitude, or in a defensive mood, however, others pick up on that and typically don’t extend as much civility.
This is one of the many reasons why it’s so important to act respectful and practice civility in our day-to-day interactions. Yes, things happen and nobody is immune to bad customer service, but many times when I hear people complain about how they’ve been treated, or why such-and-such airline messed them around, it comes from a very negative place. They tell me about the arguments that ensued, the little squabbles, and the bad reviews. I rarely hear someone admit to being pleasant or trying to smooth over the situation with kindness. Perhaps a more positive approach wouldn’t have helped the situation, but neither does getting aggressive or angry.
You can’t win everyone over. That’s merely a fact of life. But, you can catch more flies with honey than with vinegar. And if you don’t do it for other people, at least do it for yourself.