Oh, how rude

I'm not sure why people have to be rude. I don't know if I will ever figure that out, though I probably shouldn't waste time trying. Are people rude out of their own insecurity? Out of the fact that they know they're not in control? Out of the fact that they need to be in control?
I've been having to decipher lately what constitutes rudeness as well, both coming from me and coming from others. Berating or calling out in front of others? If done in seriousness, not in jest, then it's rude. Have you ever heard the phrase, "Praise in public, criticize in private?" Or "Praise, then criticize?" Well, there are people in this world who have heard neither. I am not entirely sure that it hurts my feelings when it happens to me, but so be it either way. I try not to let it get to me, but somedays.... It just bothers me because there's no cause for it. No one should have to put up with rudeness. Ever. People need to learn that.