@queenthequeen
There was no need for her to be so nasty, but I have to say, it really fucks me right off when people comment on what I buy; whether it's another customer, or a checkout operator. What I am buying is shag-all to do with anyone. I know it's sounds petty to get irked (and it is!) but it does annoy me. No doubt this woman felt the same as me.
In the past, I have been on lunch at work, and gone out to buy the Friday lunchtime cakes -12 in all sometimes - and sometimes the person serving said 'Oooooh, you'll not be able to fit in your car if you keep buying this many cakes!' 
Then I had a time where I used to enjoy a certain cake at Greggs, which was 10 minutes walk from me at the time, and I had one on a Tuesday and one on a Friday, and EVERY time I went in, this one woman said (VERY LOUDLY!) 'Oooooooh, here she is, after her custard slice!' EVERY. FUCKING. TIME. 
EVERYONE in the queue looked at me.
It got to the point where if I went to get it, and she was behind the counter, I would leave it.
That could be taken as a thinly veiled judgey comment. As in: 'are you sure you should be buying so much of that sugary crap you fatty? '
THIS ^ In spades.