evolution is great, so many cool things popped out of pure chance because of the evolutionary grinder and environmental conditions, and we ended up getting things like colorful creatures indicating either fertility or toxicity (and probably both sometimes), or a giant lizard that has such terrible oral hygiene that its bite is toxic due to the amount of bacteria in it (Komodo Dragons, very appropriately named imo), or dinosaurs turning into smol feathery things because that was the new meta (fun fact, feathers are actually significantly modified scales), and bees, among a whole ton of other things.

and then you’ve got silly little mishaps such as butt hair (probably serves a purpose but is really annoying regardless) and a nerve in your throat that wraps around one of your major blood vessels for absolutely no reason (the second one applies for basically all mammals iirc).