If we're talking about shitty human behavior...
People who FaceTime/talk on speakerphone in public.
You'll notice it's never an intelligent conversation that's happening.
I walked into a restaurant for breakfast once, place was almost empty and I took a quiet table in a corner.
Just after I ordered my coffee, guy walks in and goes straight to the table across from mine and sits down facing right at me. There were literally four people in a restaurant with probably 30 tables and he had to pick that one?
Guy then gets on his phone, loudly, in this quiet restaurant, and has the most inane conversation ever with his wife. They are literally talking about doing the laundry, did the dog go for a walk, what will you have for dinner, what’s on TV…
I’m giving this guy WTF looks, but he’s totally oblivious. Just a moron lost in his own little world.
I should have just got up and taken another table, but by then the waitress had brought my food. Ended up eating in a hurry and just getting the hell out of there.