I often find myself rambling on this topic, the limits of human observation, when trying to defend the sabermetric viewpoint. However, this wonderful article covers it all. It's intended for hockey fans, but is applicable for any sport fan and is written in plain English.
It's a long read, but worth it. Here are the some of the topics it touches on:
Cognition is Conservative
-post hoc ergo propter hoc fallacy
Attention and Memory
-human memory is re-constructive in nature
The Constraints of Time and the Perception of Means
-small sample size