Window shoppers and people who stop randomly in the middle of the pavement when you're right behind them.
Small children on scooters
Large prams taking up all available space
Cyclists who don't look
Pavement cyclists
Cars that park on pavements
Cars that are oblivious to anything outside their bubble
Cars that don't indicate
Motorbikes parked on pavements
People who walk too slowly
Pelican crossings that take ages to change - I won't wait if I have to wait too long. In fact, just Pelican crossings.
Car drivers in the rain who don't consider that they're in a nice warm box and I'm getting soaked having to wait for them to be decisive.