@Sfuandtired
I'm going with YABU. Whilst it's courteous to let someone with only 2 or 3 items in front, (if you have a trolley full,) where do you draw the line? What if there are THREE people behind with only 2 or 3 items? Are you going to let them all through? What if there are 4 or 5 people with only 2 or 3 items??? You gonna let all 4 or 5 through first?
And you do sound a BIT entitled. I have let people in front who only have 2 or 3 items, quite often. BUT if someone asked me to go in front of me I would say no, and I have before. Because it's a bloody cheek to ask.
A woman asked me once (in Morrisons,) to go in front because she had only got 3 items. I only had 5! Only 2 more than her. I said 'I have only got 2 more items than you, so I'm gonna say no' and turned my back. I heard her mutter 'stupid bitch' under her breath and shuffle off in a huff.
She tried it with the man queuing up at the checkout next to me. He had heard what happened and said no too! She was purple with rage, left her 3 items on the floor, and just left the shop.
I have also witnessed a woman with 2 items asking a woman with a big trolley full off 50-ish items, if she could go in front of her. However, 2 other people were in front of the woman asking, so she would have pushed in front of them too. (One had a basket with 6 or 7 items in, and one had a trolley with around 15 items in.)
The woman with the 50-ish items up front (who was about to be served,) said 'umm I suppose so.' As the woman asking to push in front walked forward, the man with 15 items in his trolley said 'Oh no you don't!'
The woman said 'what?! SHE said I could go in front of her.' The man said 'and to do that you will be cutting in front of me and this lady behind me coz we're both in front of you. I don't think so! Wait your turn.'
Again, the entitled queue-cutter left her items and stormed off. Probably embarrassed. (She should be!)