Even the amount of automation we have today leads to the very real danger of pilot boredom: what do they do to keep busy when the flight is on auto for most of the trip and they are stuck in the cockpit just monitoring things? At least if they could fly the plane, they would have something to do! Imagine if your job was just to monitor the computer program itself, you'd get paid (yeh!), but not having anything to do would take a toll!

Check out:

http://www.newyorker.com/science/maria-konnikova/hazards-aut...

If we automate even more, the problem just becomes worse. We could pull back on automation to keep the pilots alert, but we are increasingly relying on it to optimize resources (air space, fuel, airport take off and landing slots, and ya safety).

And...that's just it. Computers don't get bored. I suffer from some depression also (who doesn't!), but I find that my job keeps me busy enough that I can keep it in check. Imagine being a bit depressed and sitting in a cockpit doing nothing for a few hours at a time.