Dogs and jokes

It is always somehow touching for me when I hear dogs howling when they hear a siren. I wish I could tell the dog: "It's alright, don't worry, I know it sounds to you like another dog's howl, but it's actually something else... now go back to sleep."  I find particularly disturbing when somebody is withholding information that could make someone else feel better. Like for that kids' joke where you hide the snack to your classmate and you watch him searching anxiously into his backpack. How's that supposed to be funny? I hate that kind of jokes.