Crabcake

I don't pay it much mind either, but you're putting too much stock in the perfection thing. It's just an anomaly with the system. When you take a subjective topic like evaluating QB play, and try to spit out a simplified, objective number for it, there's going to be some discrepancies.

Probably 90% of the time, you and passer rating would agree on which QB played the better game. Statistically, Alex Smith had a great game (4TDs to no picks, high YPA, high completion%) so he got a really high passer rating. It's just a rudimentary answer for the question "How'd he do?"