Or the Englishman in a French restaurant who considerately warns the diner at the table who is about to eat his soup: <<Pardon, m’sieur, mais il y a un mouche en votre potage>>, and the Frenchman fishes out the soup and says <<Merci, m’sieur! Mais, ce n’est pas <un mouche>, c’est <une mouche> >>. To which the awestruck Englishman can only stammer “Bloody hell, you’ve got good eyesight!”.
I would take the fly out. And just to make my brain shuddup about it, I’d pour out a couple of mililiters–the portion that the fly ruined, of course.
Depends on the bug and my general perception of them. If it’s a fly that’s just been hanging out on a steamy pile of dog poo I throw it all out. I’ll give an ant or bee the scoop out an invoke the 5 second rule.
Narrated Abu Huraira:
The Prophet said “If a house fly falls in the drink of anyone of you, he should dip it (in the drink), for one of its wings has a disease and the other has the cure for the disease.” (Sahih al-Bukhari: Volume 4, Book 54, Number 537)