Nice post.
I think I can speak for some newer poker players (I hope I can anyway.)

I have trouble putting opponents on a range. When I do, I usually put them on a range that only beats what I hold.
I think this is two fold: I am not confident enough (because I'm inexperienced and because I am a conservative player approaching nit status (as are many new players)
So for example if I hold AQo in middle position and raise and am called by, say the button and the flop comes:
A,10,8
I put out a good sized value bet and he calls me or even re-raises me. I immediately put him on the following hole cards: AA, A10, 88, AK and nothing else. This is because if I were him (and he had my tight, if not nitty playing style) I wouldn't call with anything lower than AQ. Since I hold AQ, he probably has me beat!
See what I mean? I have trouble putting people on ranges because I stick my ultra tight requirements for calling on them and assume that if they are calling, they must have something real sweet that they are holding.

However, I don't suck at ranges,...I just need to work on it.