Movies
I hate little notes on my pillow. Like this morning. 'We're all out of cornflakes. F.U.' It took me three hours to figure out that 'F.U.' was Felix Unger. It's not your fault, Felix. It's a rotten combination.
— Oscar · The Odd Couple

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The note's initials look like a rude message until the speaker realises they stand for Felix Unger. The cornflake update becomes an accidental insult, made funnier by the three-hour delay in understanding it. The rotten combination is the pair of letters, despite their innocent explanation.
Context reviewed