My mother always told me it costs you nothing to be polite, and I try my best to live by those words. Being rude gets you very little in this world, and if you piss off the wrong person it may even have negative consequences for you.
Take this Karen
for example. Instead of approaching the returns clerk politely, she chose to be rude, which led him to seek out any and every excuse he could to deny her return and inconvenience her.