Hard question. For me, my failures generally related to social problems of my ADHD. Who I work for/with has a lot to do with my success or failure -- A lot more than my job duties.
That being said, I have always done better in environments that have built in structure, clear policies/instructions, and a high level of independence.
It is rare to find the right "mix" that allows me to go to work everyday with a positive attitude and no anxieties. I am there now and you couldn't pry me out with a crowbar - even for a job that I might have always dreamed of doing. Grass is always greener - I have learned the hard way that it is much browner on the other side of the fence.
Leaving a place where you are content - solely because you have a lingering sense of failure? Sounds like you need to lighten up about the failure and come to terms with it. Then if you make the choice to try again it will truly be because you want to and not because you are trying to make something up to yourself.
*shrug* IMO.
Failure is always difficult, if it doesn't work, well, OK, do something else. It really is ok to fail. We fail at something everyday. At least I do. I say follow your dream, but do your research and be prepared
I'm trying to decide whether to try something again or not. I have tried in a field before and failed. It's not my only option - what I'm doing now is fine. However, I'm left with that feeling of having failed, not having left to move on by choice. And, at the same time, I also know it's sometimes better to let dead dogs stay - to cut ones losses, etc.
I have a good reputation doing what I'm doing now - for the most part, and a reputation as difficult in the other field. I really don't know whether I was not successful because of the add, circumstances, or if it was because it wasn't "my field."
I don't have a perfect handle on my add now - but I pretty well have it under control most of the time now.
I wonder how people logically decide whether to try something again when there's so much natural emotion tied up in having failed, etc.