Waiter, there's a fly in my soup.
Don't shout so loud, sir, they'll all want one.

Waiter, what's this insect doing in my soup?
Looks like the butterfly stroke, sir.

Waiter, you've got your thumb in my soup.
Don't worry, sir, it's not very hot.

And, from the Two Ronnies:
A waiter in a top London restaurant was sacked today for having his thumb in the soup when he served it. A topless waitress has been dismissed for two similar offences.