I've got one that's kind of a cross between two of yours -- extreme stupidity leading to entirely daft dramatic misunderstandings. You know, where A sees B give C a comforting hug and instead of wondering why C needs a comforting hug, gets all Oh Noes B Loves C And Not Me I Will Go Off And Become A Hooker/Fall In A Ravine/Be Tortured By Bad Guys. At which point I usually hope A will come to a bad end and B really does love C, who actually talks to people about problems (hence the comforting hug or whatever).