Overall, I was an unhappy child, but this was the result of a combination of events, not entirely due to religion. Outcast at school, violent father, cold and isolated depressed mother, outcast at the local hall for the most part. This formula will not make for a happy child, although I was quite content when accepted by my kind.
In grade school I was the only dub besides my sister who was holier than thou. In HS there was 1 other kid, but he was a complete jerk. The real backstabber elder's kid type. In the limited association I had with him, my parents would get calls from his father and I would get punished for stuff this jerk actually made up.
At the hall, being a spiritual fatherless child, I was pretty much an outcast except for 1 kid with whom I am still friends 35 years later (we play video games or cards almost every weekend). I did manage, once in Senior HS, after I got a license, to establish friendships with other dubs at neighboring halls. I really would not have minded being dub if I could have skipped service, meeting prep, and that awful BS every week. The holidays didn't bother me because I didn't know what I was missing.
I would party w my dub friends, drinking, cruising, going to clubs. Then if I got caught I kept silent about who I was with, so no one else would get in trouble. The ones I partied with the most went on to bethel or became elders/ms.
I didn't hate the religion, I hated the way it was shoved down my throat. I hated the authority the elders had over my household. I hated having no free time. I hated having to knock on classmates doors, which stank so bad for a skinny outcast kid living in a bigotted area where I was confused as a "jew" and beaten by various groups of hate-mongering bigots. Yes, I proudly endured the persecution for da troof. I didn't really learn to hate the religion until after HS. Then I choked it down, bought it lock, stock, n barrel until I realized I didn't have to anymore when they tried to control my own (adult) household by telling me and my wife how to dress, what to do, etc. I was about 23 or so.
I would never subject my children to that life, and for that they have expressed gratitude. They have seen the inside of the KH thanks to my ex's parents. But one or two trips caused them to request to never attend again. I can't imagine how tough it must have been for someone who's parents converted and went full fledged into it if the kid was in their teens already.