We've all done it, had our head turned by something in a shop, talked ourselves out of it and then regretted it.
What's your 'one that got away'?
Currently I'm kicking myself over a pair of £17 sunglasses, talked myself out of it because I had a decent pair at home only to go home and find they were damaged beyond repair . Went back to the shop and of course, alas, they had gone !