I think that what you are telling us is something most guitar players can relate to. About every guitar player will hit a wall at a certain point which stops them from really getting to that next level. And I totally agree with what Kutulu says: Not one guitar player is totally satisfied with their guitar playing.
When I first came to this site as an intermediate player I still took the Guitar Fundamentals lesson before actually doing some of the Rock/Blues/Country courses in the Core Learning System. I actually learned quite a bit.
The most important thing for me when playing guitar is next to the part of learning something difficult is also playing those things that are a lot of fun. It keeps me motivated and actually wanting to practice the harder bits. When you only practice those things that are difficult it might become a frustrating and joyless journey, so I keep playing those things that I really enjoy.
Eventually, when you are finally able to play that difficult part, it gives (me) an unbelievable sense of achievement.
And I just want to add one more important thing. Some guitar players get frustrated because they expect a bit too much in terms of being able to play something advanced in a short amount of time. It can sometimes take a lot of time to master those difficult guitar parts. The key is being patient!
It's important to take your time when trying to master the difficult things. This usually means to slow down parts to such a level that you can't do anything but play it right. If that means to slow it down to 40 bpm that's totally ok. Practice it right and the speed to play it normal will come. Also, a lot of guitar players tend to move away from those difficult parts and start playing what that already can play when practicing. When praticing it is important to focus on those things you really want to learn.
And on one final note: Don't get frustrated. The time you are frustrated is time you could be practicing.
Hope that helps you in some way breaking down that wall.
Please let us know what exactly you are struggeling with. Perhaps we or some of the instructors here can give you some tips on improving on a certain subject.
JJ
