They compare you unfavorably to other people.
As in:
“That pie you brought today looks like a nice little treat. But you should have seen the cake cousin Ruthie brought last week!
“It was the most amazing thing I have ever seen! So many layers and trimmings and textures and flavors!
]
“It was so delicious that everyone within miles was lining up for a slice!
“It could have fed an army–and basically, it did!
“I have no idea where she even got such an amazing cake, but I will never forget it. It was sheer perfection–and she said it only cost five dollars!
“Can you believe that? It was worth millions! No, you couldn’t even put a price on it, it was that astounding!
“Anyway, let’s try yours.”