I hate

Yeah, hate this - WELL annoying, happened to me the other night with some fat bitch. She came back and said "Excuse me, I was there" I just turned round and said, "No, you're basket's there but you fucked off...I'm here now and I've gotta get home"

this is exactly perfect response.

With petrol stations I used to get dead arsey about who was in which que and who was 'technically' first, but then I got older and wiser (dizzy wise old age of 24) and now just choose one then relax with some music (which may or may not relax the rest of the forecourt, but meh).

With bars I use the soviet method of queing, which is to basically breath down the neck of the person infront to prevent anyone squeezing in the gap. Anyone TRIES to squeeze in the gap I just slowly turn into them, push with chest/shoulders until they are far enough away, then resume cramming where I was before. The key is to never speak, and never make eye contact or remove hands from pockets, just slowly but firmly push them with your chest.
Reason its called the soviet method is in essentially all ex-soviet countries he who is at the line first, gets first, nothing to do with who has stood their the longest. I learnt this the hard way many times when over there.

I.E. stood in a bank, theres a man with a gun on the door, another by the counter, yet if you leave more than 8" (depth of a human torso) between you and the person infront, another person will just calmly walk from the back and slowly but firmly wedge themselves into the 8" gap, hands in pockets, eyes front, no words.