There’s lots on here that have been mentioned repeatedly, so they are obviously seen as bad mannered by many!
People who cough without putting a hand over their mouth (a pet hate of mine even pre covid)
People talking into their phone loudly or when it’s on speakerphone
People putting their feet up on the seats infront on public transport or putting a bag on the seat next to them ( when the bus/train is busy)🤨
Clipping nails - I saw this too many times on the tube, when I lived in London🤢
People letting their dog/s run up to people when they are eating (happened a few times) worse one was at the beach, the owners let their dog run into our beach tent thing , our toddler was so startled, dog clambering over all our food, sand everywhere. They didn’t even try to recall the dog or come over to get the dog away , just looked at us, thinking it was funny. Lazy, gormless owners - not the dogs fault.
When people don’t say thanks to cars stopping at the zebra crossing, or when a driver pretends they haven’t seen you at the zebra crossing and just drives through.