Upvote for cat. Cats have the hacker nature, after all. :)
I'd love to setup some automated webcam -> nerf gun system to automatically hit any cat in the head if they enter my property. Maybe a project for when I'm old and bitter and have time on my hands :)
If you live anywhere near other people, a cat is probably the most antisocial pet to have. (Assuming you let them out on their own)
Nothing like being woken up at 3am to two cats duking it out. Or having you garden ruined because the neighborhood cats like to poop there.
Very irritating.