When a girl declares their love for you, and the only response you give is "oh".
When you have to work with someone you don't like, you have to maintain a good enough relationship to work with them, when all you both want to do is punch each other. Which leads to really awkward small talk, that neither of you enjoy.
When people don't move to the right to avoid walking into people, they go left, and then you do that stupid ****ing dance where you both try to get out of each others way but fail to do so, all the time saying "sorry, sorry, oops, sorry!" Always step to the right, it's the law of the pavement.
Bumping into an ex girlfriend and her new boyfriend in a take away, while you're wearing week old jeans and a football top because everything else is in the wash and you couldn't be arsed to shave or shower that day. You're also clutching a new computer game in a HMV bag, and then having to explain you have a shit part time job, while they are at university and about to embark on a world tour envolving a lot of sun, sea and sex.
Accidently engaging a clipboard vulture in conversation, in the hope you could get their phone number, then having to pretend to give a shit about Greenpeace or some other pointless crap.