I believe that there are some of us who just cant be good at certain things. For example, I can take as many drawing classes as I want and practice forever, but I will never be a Disney animator.
On a similar note, some of us are more mechanically inclined than others. I have watched videos, spoke with LBS and friends, and read books, but bike repair just doesnt seem to be my thing. I can change a tire, but thats about it (the same with cars, tires and oil is all I can do). I rewrapped my bars, and that came out ok (on the fifth try) So now that my derailer is out of wack from my "tuning" and I want to replace my dowtube shifters with bar end, it is off the LBS I go. They usually dont charge much for labor, because their parts are marked up, just hope the shifter change is under $100........