The common theme here which is inconsiderate people. Line cutters, people changing their babies' diapers on park benches and on buses, people throwing trash on the ground, people feeding the ducks and birds, people yelling and threatening their kids.
It makes me twitch when someone comes home from WDW and declares that they had the worst time and it turns out it's all because they didn't do even the bare minimum research. "We couldn't get in anywhere to eat" "All these people paid to have Fastpasses to get in the front of the line meanwhile we waited 2 hours" "My daughter loves (insert character) and they weren't even there!" "It turns out Harry Potter is in a whole other park miles away!"