mom: watch it, I don't want you to get dirty..
son: but... it's only a dog.
mom: dogs are dirty... all pets that are furry are dirty and I don't want dirt anywhere.
son (sobbing): but mom, I wanna have a pet... like a hamster.
mom: no, you can't have one.. it would get our flat filthy, it's furry.
son (sobbing): please mom, can't we get a hamster, I promise I'll clean up...
mom: no, absolutely not. You can only have pets like snakes or fish.
son: ..but I'm afraid of snakes.
mom: so, there you have it... you'll get a fish... only if you promise to feed it and clean it's bowl.