The fact that football coaches don't go for it on fourth down is actually really interesting. It's basically a question of risk aversion -- kicking on fourth down is "safe", while going for it is expected-value-positive but highly risky.
In real life, it makes some sense to be risk averse. Money has decreasing utility the more of it you have, so it's completely rational to refuse to bet your life savings even if there's a 51% chance you'll win. In a game like football, however, utility is necessarily proportional to the probability that you'll win the game. If a play increases that probability on average, it's the correct play no matter how risky it is. Football coaches are treating the probability of winning as if it had decreasing utility. They're being irrationally risk averse.
Once you start looking for irrational risk aversion in games, you start seeing it everywhere. It comes up just as often in Jeopardy as it does in football -- people tend to risk less than they should when they hit a daily double (early in the game, you should almost always bet everything). Funny enough, I don't think Watson got it right either -- in the second half of the first match, it made a relatively small bet when the rational strategy was probably to bet everything.
