But I'm not wearing a clown suit
A statement that serves as an acknowledgement among vendors that no matter how amazing a finished product is, the client will invariably find something to complain about or request a change that actually makes it worse. The client does so while wearing a metaphorical clown suit.
We just completed the client's new website, and it exceeded their specifications in every way. I think it turned out great, but I'm not wearing a clown suit.