Humans are at a war with nature. We build walled castles to keep all the monsters out, so in response nature sends her grossest, nastiest beasts to squirm into our fortresses. Sure, pigeons and roaches could have been as pretty as parrots and butterflies, but we don’t deserve that. In a big city we’re stuck with critters as gross and gray as the concrete we used to build it.
The only way to fight nature is with nature, so that’s why you get a cat. Did you know that the leading evolutionary theory is that cats domesticated themselves? A billion years ago some feral cats found a human settlement and decided, “Hey, if we appear harmless and bring them a dead mouse every now and then they’ll feed and protect us.” That’s also why your cat might kill a bug one day then couldn’t give less of a shit about another bug the next day. Once their quota has been filled they’re off the clock and back to making us scoop their shit.
Basically what I’m saying is that nature tricked us and snuck in yet another gross, nasty beast by wrapping it in a cute fursuit. It’s time to admit we’ll never win this war. There’s gonna be roaches on spaceships.