I'm kind of the same, although slightly different.
I played Guitar Hero to death when i had it - but only on medium difficulty. I pretty much 100%'d every song on medium, and rocked hard when doing so. I was awesome.
However, bump it up to difficult, and i couldn't do it. For some reason i lacked any kind of independent movement of my little finger, so when they introduced a fifth colour, i couldn't handle it, and failed most of the difficult songs. I've never experienced such a ramp up in difficulty from one level to the next in a game before.
Anywho, still played the game to death, even though i sucked at it.