I have put literally minutes of thought into it, and I am now ready to present my alternative theory to evolution, one which explains all the sub-optimal anomalies we see in nature.
The theory posits that God created the Universe, but put most of his efforts into some planet other than Earth, say, Rigel VII. The life on that planet is AWESOME. Efficient, highly homeostatic, and with sleek, eye-popping design. God put a lot of thought into that planet's biosphere, and it shows. (Not to us, though. We'll never see it.)
Meanwhile, God delegated the work of creating life on backwater worlds such as Earth to a team of elves, or something. These elves were definitely not the "A" team of bio-designers. One of them screwed up and created an eye that inverted the image. Rather than fix this problem (it was nearly five o'clock), they threw together a quick kludge whereby extra processing power from the brain turns the image right-side up. It works OK, and as long as no one looks at their work too closely, no one will be the wiser.
Another elf routed the esophagus of the giant squid through its freaking BRAIN. "What were you thinking here!?" the head elf asked him. "If he takes too big a bite, it will kill him!"
"Relax," said the underling. "It's a SQUID. Who gives a crap?"
It was nearly time for happy hour, so they came to a compromise whereby the squid would live so far underwater that it would take thousands of years for anyone to detect the mistake. By then, both elves would have moved on to other jobs.
I'm a software developer, and believe me...I have seen this sort of thing many, MANY times. People throw stuff together without thinking it through. When bugs are found (which they always are), they throw together a fix that works around the problem. Eventually, the code becomes a tangled mess of counter-productive instructions as well as huge sections of completely inert stuff that represents many thousands of man-hours of wasted time. But, it works, and it's too much trouble to fix it.
This type of organically designed code is strangely similar to DNA.