You're not getting what you want or, rather, someone is bothering you. Face-to-face confrontation isn't always the answer. Sometimes, just sometimes, a little note rife with sarcasm, wit, and/or anger is all you need. While these people duke it out via notes, we get to see the results and laugh.
A gentle, polite reminder *wink wink*
So, you steal someone's salad dressing and they retaliate, so the obvious thing is to do it back.
Words? Sometimes pictures are more powerful