What's wrong with me Doc'?

A man visited his psychiatrist and told him that he thought he was turning into a packet of biscuits.

"What sort of biscuits?' asked the psychiatrist.

"Square ones," said the man.

"With little holes in them?" asked the psychiatrist.

"Yes doc," said the man with relief, "That's it exactly. What is wrong with me?"

Spoiler:

"You're crackers," said the psychiatrist.