Now What Did I Do Wrong?

A married man is attending his mother-in-law's funeral, and eventually notices that his wife, sitting beside him, seems annoyed and is getting angrier by the minute.
"What's the matter?" whispers the husband.
The wife hisses under her breath to him, "Just wait until we get home, buster! You are in big, BIG trouble!"
The husband frowns and asks, "What did I do?!"
"BIG trouble!" the wife threatens!
The husband looks around helplessly, then down at his lap. Suddenly, he realizes the problem.
"Oh, I get it! Is it because I'm not sharing my popcorn?"