The actor Sandy Kenyon and that look he gives make it even funnier than it would be without him.
Grants post made me realize that we could have a whole thread on Columbo's car just by itself. For instance, in A Friend in Deed. when he goes to see Charlie Shoop that interaction is hilarious. Shoop wants to know if there's 20 or 30,000 miles on the car. And then at the end of the conversation, he said that he would give him $200 for it in a trade. Hilarious stuff