I was accused of queue barging by a nice little old lady in Tesco a few days ago. It was after midnight and I was at a 24hr branch and I was at one of the self service tills that was working (2 out of 6 were) with nobody waiting. I had forgotten something from my list so ran off and got it, total time away from the till 30 seconds max. The OAP is now standing two feet away from my till when I get back and as I go to scan my item she says rather loudly "There is a queue you know".

I turned round to look at her and was about let rip, when I thought better of it and merely said (and I wish I had had the presence of mind to do a Basil Fawlty voice):

"I'm so sorry would you like to use this till then? If you're happy to pay for the rest of my shopping then be my guest, otherwise do you mind if I continue?"

She did actually manage to say sorry but then spoilt slightly it by making comments about the youth of today, was secretly quite pleased that I was still considered a youth!