I wouldn't call it worthless.
It did instill certain good traits... would I have received those traits without the influence of the JW religion? Maybe, maybe not, but I can only assume at this point in life that it did help.
The Ministry School did help me in being a better public speaker, not that I'm a good speaker now but I'm better than if I had never received any training in it.
I did make some friends, friends that I have to this day despite my fading away from being an active member. Yea, I'm sure I could have made other friends outside of the religion, but I'm trying hard to look at the positive of my upbringing instead of bitching about it all the time.
I can't change my past, I can't change who I was, how I was brought up. I'm not overly glad that I was raised a JW but since I can't go back and change it, I might as well accept the good, lament the bad and move on in being an ex-JW without too much bitterness or anger.
What one makes of ones past experiences can shape what one becomes in the future. If one only grumbles about how bad it was to be a JW and not having a "normal" upbringing, then one is probably doomed to being a miserable person from here on out, willing to blame the past than to willingly accept the challenges of our life now. If you can't come to terms with your past, how can you expect to overcome issues that may arise now and in the future if it's too easy to blame someone else?