You are walking down the street and see a girl with a perfect body
and beautiful hair just ahead of you. You think she must be very
good looking and want to see her face. You think about hurrying on
ahead and sneaking a look back, or somehow making her turn round so
you can see her face. Anyway, somehow you manage to get a look at
her face and it turns out to be very plain or downright ugly.

Someone once told me there was a word in Japanese for this situation.
If anyone knows the word or an english equivalent, please let me know.