Yes, I've done this. I wrote everything that's going right with my life first, and then I wrote what was going wrong with my life and assigned two additional metrics to each point: the difficulty of solving it and the probability (low, medium, or high) of solving it.
I think all it did was cement my decision to CTB. Not because my problems were unsolvable, but because I saw just how much effort, and perhaps more importantly, luck, they'd require to solve. Also, there were actually not that many points on the list of problems (though they were all pretty major, like work and love), so it was possible for me to envision what my life could look like after solving them, and I realized that even that "good" life wasn't worth it to me.
As with @ijustwishtodie, this exercise essentially just made me realize that my issue wasn't so much with my current life but with existence itself. The hypothetical life I could have with those problems solved doesn't appeal to me because I'd still have to exist.