Complete dental anarchy?
Not to mention the nightmare that is wisdom tooth removal -- those bastards try to cram their way into the jaw so tightly that nothing short of surgery can remove them. Again, it seems like a straight design flaw -- why in the hell would you not have room in your mouth for your own teeth?
It Has to Be That Way Because:
Before humanity got a taste for flesh, vegetation was our only source of nutrition. But the thing about roots and leaves and nuts is that you need a lot of it to get enough protein to keep on living. So imagine the teeth it would take to grind down that kind of diet all day long. You can go look at a horse, if it helps.
Oh hey, we loved you in Reservoir Dogs, Mr Buscemi.
Once our big ol' Chiclet teeth had their way with wood pulp or whatever else we were managing to swallow for sustenance, our digestive systems went to work. Digesting all of those twigs and shit sapped whatever energy we had left -- which left zilch for our brains.
And then something happened. Someone somewhere figured out, "Hey, meat!" And then they learned how to cook it. Beginning about 2.3 million years ago, humanity started getting enough protein to direct a little more to the brain and a little less to the shitter. It didn't take too long to figure out tools that made our fangs even more worthless.
As a result of this softer brain-fuel diet, our jaws are shrinking, crowding out the worthless teeth and inflicting headgear on scores of awkward preteens. At least we have the brain power to generate the income that it takes to pay for the headgear, though.
And the strong tool-using hands to bully someone into a miserable childhood.
#3. We Choke on Food Because We Evolved the Ability to Speak
Quick! When was the last time you had to give your dog the Heimlich maneuver? Never? (Please say never.) The idea of animals choking to death is as foreign as the idea of humans who can lick clean their own crotch, yet more than 3,000 people a year manage to accidentally choke to death.
Eating in a hurry, eating while laughing or just plain old not chewing enough can end it all within minutes. How in the hell did we evolve so that you can kill a healthy man just by tickling him while he's trying to swallow some falafel?
"My other technique involves asking the victim for the time while he's carrying a scalding hot drink."
Ask your larynx. You can literally do that, because you have one, and it happens to be the reason you can't breathe and swallow at the same time.
It Has to Be That Way Because:
You hopefully already know that the only reason you can talk is because you have vocal cords (or folds), which are located a couple of inches down your throat, in your larynx. The cords are down there instead of, say, right at the back of your mouth, because being down there lets you make a much wider range of sounds (think of your head as a musical instrument). That design means that instead of crude grunts, you can spit the kind of sick rhymes that let humans consistently win battle raps against almost every other species on earth.
But this kitty can play the trumpet real fine.
But that setup also lets food get caught in there, and stops you from breathing in the process.
You know from basic biology that inside your neck meat are two tubes. One, the esophagus, sits in the back of your throat and carries food down to the digestion parts. The other, the larynx, sits on top of the trachea, which takes air down to your breathing parts. Because the larynx is positioned down in the throat a bit to give us the ability to say fancy words to each other, the air tube can't connect directly to our sinuses (which would let us keep breathing through our nose whether or not we had a doughnut crammed in the other tube). Instead, the two tubes share a little hallway before branching off to go their separate directions, and one hunk of bratwurst can block them both.