Personal rudeness... whether it's trash-talking online because you can hide behind the screen, or people constantly on their phones when you are supposed to be spending time together, or texting while driving, or using the f-bomb and other swears as a normal part of conversation, etc. It's time to return to treating others with respect (until they prove to you they don't deserve it) instead of expecting people to prove themselves worthy before you'll respect them.
Overly-reactive personal sensitivities... People don't know how to handle opinions or how to let them roll off their backs. People express opinions, you are free to agree/disagree, but someone's opinion is NOT "shaming" you (grrrr, I hate that word) or "being judge" (another grrrr...) unless they become personally rude (see above). There is a huge difference between someone saying "I don't particularly like that dress on you" and saying "That dress makes you look like a fat pig."
A corollary to this is the micro-aggression. I have a colleague who teaches pharmacological biochemistry at the college level, through a School of Pharmacy. He received a nasty-gram from a student AND her mother for his "unbelievably insensitive" discussion of Anabuse, a drug used to counteract alcohol poisoning. HOW could he discuss this without warnings, HER father is an alcoholic, how could he be so rude and insensitive, etc. Their accusations are unfounded; I know this guy, I've sat in on his lectures, and he is NEVER snarky or improper in class. This is just another case of someone who hasn't learned to handle reality. More and more we see teens/twenties who simply cannot manage their emotions, whose feelings are hurt by almost everything. I don't understand how we've let this generation become this way. During WWII, 18 year olds grabbed a gun and got off a boat onto Omaha Beach, watching their friends be gunned down by the Germans and facing their own possible deaths. These days, 18 year olds can't tolerate discussions about diseases, etc.? How did this happen?? When did people become so overly sensitive and thin-skinned?