So I put my lunch in the microwave just now and left the kitchen to use the bathroom.

When I returned, a second container was in the microwave with mine.

I don't know whose it is. The kitchen was empty. My container is not labeled, so my first instinct, being that somebody I know quite well was playing a trick on me, can't be right.

I'm so troubled I had to stop on my way back to my office to share the incident with two colleagues.