If my math is correct, you've spent between 200 - 600 hours on GF 1. That's way way beyond the pale fror anyone. I suspect that you are getting stuck on lessons by trying to match the rate of the instructor when playing the songs against a backing track. If that's the case, please realize that doing so is crazy. Both Lisa and Anders are professional guitarist who are playing those tracks at a pace that is comfortable for them, not a beginner. Being able to play as fast as the instructors is something to aspire to over months or even years - not on your first go-around.

Use the rate tabs on the left of the video screen to slow it down to what you can play comfortably. Once you can play it through consistently.... at any speed, move to the next lesson. You can always come back later to work on speed. If it's not the play-along tracks that you're getting stuck on, then you should definitely take the advice of Willian MG and seek professional lessons on this site so you can diagnose what's going so wrong.

Nicolai