@ Rodman
I actually went back and played almost every song rated 1, 2, and 3 in January and February just to get back into playing Bass. 1s and 2s were both very easy but 3s tended to be very hit or miss. Some were fun and easy and others I just quit back to menu because it felt like there was no way it was going to happen. That could be because some of them utilize techniques or patterns I haven't practiced at all. I think if I went through it again now I wouldn't feel that way.
4s most definitely cross that line where I appreciate the complexity and it's more fun to play but I have to buckle down. I'm in the process of working through all the past 4s from old championship weeks but that's going a lot slower since I tend to be more focused on the current week's songs so I only do that if I have extra free time.
Whenever the week's songs are more difficult I try to just see it as a challenge and rise to the occasion. I won't lie though there have been definite moments of frustration in there when I just stopped playing because I didn't feel like I could do it. That being said I'm seeing real improvement and I feel like my score on Two Tickets to Paradise this week is proof of that. I was just flailing away on the fretboard the first time I played it and I think I got somewhere in the 60s or 70s on accuracy. Anyway I don't have any solutions or ideas I just wanted to give some input on my experience.