So you have a hole in your body, right? It's used to breathe in and out. But wait, it's also used to eat and drink, but you should never do both at the same time! Fortunately, there's a nifty switcher between the esophagus and the trachea. Of course sometimes it fails, leading to extremely uncomfortable fits of cough and possibly death.

But wait, you have another couple of holes! These are made for breathing too, but you should never ever attempt to eat or drink from them. Oh and they merge with the main hole before the switch as well.

Whoever coined the term "intelligent" design should be slapped across the face.