I'll admit I'm giggling at those folks in this thread that are unapologetic for either their or their loved ones' rudeness/bad behavior.
Would you lean towards excusing other rude and/or bad behaviors?
Your 6-year-old smacks people just for fun. Would you say, "Well, little Johnny, we've tried telling him that he shouldn't hit, but it's just the way he is."
Or grandpa calls people of color naughty names. "Well, grandpa, he says he knows it's not okay to call the guy walking down the street the n-word, but his daddy did it and it's just a part of his vocabulary, so please excuse the hate-filled language."
What if your hubby farts in public? "Well, Johnny thinks it's funny. Just ignore him."
Your nephew kicks cats. "He doesn't kick hard enough to hurt 'em, so we ignore his behavior because we think if you give bad behavior too much attention, you'll only make that behavior worse."
Really, if I had a person in my life who was perpetually late, which let's be clear here, IS rude, we wouldn't be friendly any longer. No, I don't have to accept your rudeness. No, I don't have to take you as you are. My time is just as valuable as your time, only your tardiness shows you think just the opposite.