I get this weird feeling when I have something in the clipboard. If it's something I have copied it's a kind of pregnant "holding onto something" feeling. If it's something I've cut, then I have an additional anxiety that I will have a crash, forget about it, or most likely of all, copy again before I have pasted.
I have the same feeling with halfway filled out forms on web pages.
Others have mentioned it as well:
Seth calls it Control-C anxiety
Ruby's cartoon foxes
have their legs in photoshop's clipboard. Cripes!! Holy!! Pray it's OSX, man!!!