+ 1, annoying.
However, by far my biggest pet peeve, is people trying the stuff on when it is obvious beforehand it wont work. It one thing to have a near miss, quite another to miss by a mile. A huge fat dude needed his wife to help him take off a 40R jacket I had just looked at. He wanted the jacket because it was Hugo Boss but probably was thinking he could lose some weight. Judging by that debacle, he would need to lose all his weight, his entire mass (or at least 99% of it) .
Also saw a wee little chap try on a jacket around 10 sizes too big and then walk off with it. It was nothing special so I doubt he was a flipper but I did think to myself "for that jacket to work, steroids, a diet high in protein / saturated fat, and rigorous powerlifing sessions were urgently required. This would have to be conducted for several years of course, that is a given".
I picked up a Hugo Boss suit for a quick flip and listed it locally. This guy came and tried it on. He was maybe a 42S and the suit was a large 44. He was swimming in the jacket. The sleeves came down to his second knuckle and the jacket length was a good 4 inches too long; but he said his tailor could adjust it. I didn't blow the sale by arguing the point, but it still makes me wonder.