Reshape one's foot to try to fit into a new shoe.
Zheng Man Buys His Shoes
In the past there lived a foolish man in a small kingdom called Zheng. One day he wanted to buy himself a pair of new shoes. He measured his feet with a ruler first and wrote down his size. But he was in such a hurry to set out that he left it at home.
When he arrived at a shoe shop, he felt in the pocket only to find that it was not there. So he said apologetically, 'I have left the measurement at home and don't know the size. I'll fetch it in one minute.' With these words he hurried off as fast as his legs could carry him.
He ran back home, found it and then to the shop again. But still it took him quite a while and the shop was already closed then. He had gone to all this trouble for nothing and did not get his shoes.
Then someone asked him, 'Did you buy the shoes for yourself or someone else?' 'For myself, of course.' he answered. 'Then why don't you try the shoes on by yourself?'