I have millions, especially as I don't drive, specific to walking and public transport. A novel follows:
On a narrow pavement when groups of 3 or couples expect you to move into the gutter for them. Especially when I'm walking in a pair and the other pair don't move into single file too, like they think they're more worthy of the pavement. I've taken to shoulder checking them or barging straight through when they do this. It's the only way they'll learn.
If I'm walking on a narrow path next to grass (or during the pandemic narrow pavement next to the road) and I move on to the grass or road for the other person and they don't say thank you. I now have a rule of only doing this for mums with buggies or elderly/disabled people now.
People putting their feet up/across seats on public transport, double points if they take their shoes off.
Drivers who stop across the space designated for pedestrians to walk. I often feel like banging on the hood of their car. And drivers who don't indicate and almost run you over when you're crossing the road. Or indicate and don't turn, leaving you dithering.
People in supermarkets who block an aisle with their trolley while they browse. My mum does this and it drives me mad. Or people who pause in front of a queue, but aren't queuing. Again, people not acknowledging you when you stop to let them out - or worse, don't tell you they're not moving past, and leave you to turn all the way around like an idiot.
People not thanking you for holding a door open for them. At uni (must be a class thing) about 20 people passed through a door I held open without acknowledging.
Maybe controversial, but I don't like when I'm struggling to put a heavy bag in the overhead compartment (especially now I'm pregnant) and a man doesn't offer to help.
When you're with someone who meets a friend you don't know, and the mutual friend doesn't bother to make introductions, and leaves you a gooseberry.
Maybe also controversial, but when (in the UK) 2 people you're in the middle of a conversation with start to converse in French/Spanish leaving you out.
Might be the middle Eastern in me, but people not at least pretending to protest when you offer to pay a bill. People not offering you food or drink when you go to their house. Again probably a cultural thing.
I have also noticed (as a youngish person) that some young people now feel very comfortable to make condescending comments about people they perceive as not having explored their gender identity enough.