It's old women that get on my nerves. When I've finished my hard day's shift, I'm quite happy to sit on the bus, plug into my iPod and let the journey go by. I also pay for my seat, so why should I have to give up my seat when it's busy for some old bat who's stupid enough to go shopping when people are going home from their work.
Not only that, they stare at you in the hope that their mental power will make you give up your seat for them. I say NO! If they can walk about the shops for a couple of hours and stand at a bus stop, they are perfectly capable of standing on a sodding bus if it's busy.
Obvious exceptions to this rule are those with walking difficulties, pregnant women and blind people.