I understand what you mean about hearing everything! It's odd, because often I have to ask people to repeat themselves, but it's not because I have a hard time hearing. My 5th grade teacher even had me tested for hearing difficulties. The truth is I hear too well (even after years of death metal concerts attended sans ear protection) ... and I can't necessarily tune other stuff out (or my own thoughts) well enough to actually pay attention to what someone has said.

I think it's telling that I can still hear the refresh rate on most CRTs at nearly 30 :)