My worst time period was age 10 to 13. I was already too old for the simple pleasures of childhood, but still too young for the advantages of adolescence. So in a nutshell, I had the worst of both worlds: no longer allowed to own childhood toys, and not allowed to walk around town by myself. That's when I spent a lot of time praying to god to take my life, and when that didn't happen, I became an atheist.
Also, roughly when I was in 3rd grade, my parents started some strange crusade against "kid stuff", to get me to "grow up faster". What compounded it is that I had when my family moved across the country when I was 10, I had to leave my childhood toys behind and wasn't allowed to replace them after moving. I compensated by getting very heavily into Legos, and my parents were OK with that.
On the plus side, as my 13th birthday present, I was given permission to take city buses by myself, with a requirement to be back before dark or by 8:00 PM, whichever is earlier. So I no longer had to beg and plead to go to a museum or my favorite store. I'd just take the bus fare and spending money from my allowance savings, get on a bus, and go to town. By myself, yes, but it was better than staying home.