Freedom? Where do you live? Freedom is childhood. Biggest worry is where your next cookie is coming from... mmmmmmmmm cookies. 
Childhood freedom is an illusion IMO... I don't have anyone telling me to get up to go to school, or to do homework, or to go to bed on time, or what to eat, what friends I can or can't have, what clothes to wear etc. I think people sometimes get nostalgic for childhood without realizing the benefits of being an adult. Sure, there's a cost to every action you take as an adult, but at least you get to be able to make that choice for yourself instead of having someone else make it for you. I choose for myself whether or not to go to work today, or pay my taxes, or eat a ton of junk food before bed, and so forth.
Edit - I guess people get nostalgic for the lack of responsibility in childhood... but that's only half the equation! Less responsibility + fewer choices < more responsibility + more choices. 
Newpz. Nothing to do with responsibility from my perspective. Only, possibly, in the fact that you don't have any idea what responsibility is... but not really. The thing so wonderful about childhood is that everything is new! You have no idea about the world, and every experience is part of your genesis. I really wish I could
feel as I felt as a child, because I don't think anyone can really remember it due to neurological development. I can imagine though, and it must have been incredible!
As you grow older, you learn of the world and its impurities/corruption/whatevs. The freedom I refer to is the carefree mentality that is no longer an option as you grow up. I suppose responsibility does play a factor in that, but it isn't the entirety of the picture. The world is incredible as a child, and it sucks as an adult. People suck, societal standards suck, morality has been sucked dry... and this generally equates to life sucking. Unless you choose to "just live your life," intentionally blinding yourself to all that is wrong. Surely, many people live "happily" in an extrinsic sense, but noone is oblivious to the superficiality of such "happiness." At least, I can't imagine anyone being that daft.
