Why on earth do people feel the intense need to take those bloody pull-along suitcases out with them shopping? I've lost track of the number of times I've been walking down Oxford St, and have almost been tripped over by one of them.
Not only is the suitcase itself bad enough, but the person pulling it nearly always seems intent on letting it follow them at complete arms' length, thereby taking up as much room behind them as possible.
And it gets worse still when they try and take them onto the underground. It's as if a part of their brain has become completely disabled (i.e. the common-sense part) - you don't get to the escalator, and then think "oh, I'd better do something with my suitcase". You realise that you're about to step onto an escalator, and so pick your damn suitcase up first. This way, you don't trip half the people behind you up.
And realising that one needs a ticket to get through the ticket barrier before getting to the ticket barrier would be nice.
I don't know how many times I've been stuck behind someone who has been fumbling in their purse/pocket/wallet etc for their ticket whilst stood at the barrier. If you're really stupid enough not to realise that, 'hey, seeing as I needed a ticket to get through a barrier to get in, I may well need it to get out', then at least have the courtesy to step aside, and let other people get through the barrier while you stand and be disorganised!
Ok, I'm done ranting now!