There will always be people that miss things the way they were back in the day, because they were the best times ever dammit. I'm sure looking back, it all seems like the time of your life; no job, no bills, no planning for your future all the damn time. You saw every single person in your social circle every day, as well as all the people in every other social circle. Every time you had to do anything remotely complicated, there was plenty of people around to hold your hand and protect you from the cold hard truths of reality. Hell, even making your own decisions those days was optional. And while I can to some extent understand people's yearning for the simpler times of their lives, more often than not, the same people that want to be young again are the same people that are unhappy with the way their life has played out so far.
In the more retarded realm of getting another shot at childhood, most people have their own individual tirades about what they would do if they knew what they knew now(You know, like that one song everyone uses in commercials when they talk about life insurance or cars and shit). Naturally, there are some things you could change in terms of actions with direct consequences, but even with the right information you can't really improve your shitty life. Not because of the situation, but because if you were a responsible human being, you wouldn't be relying on a time travel oriented second shot to fix all your problems in the first place.
Being a kid fucking sucks, mostly because:
-You don't get to dress yourself, and the people that do dress you want you to look as ridiculous as possible, because they resent being your legal guardians.
-Your hopes, dreams, and feelings are taken seriously by absolutely no one(not that this ever changes much when you get older).
-Nothing important happens except for traumatic incidents that will indefinitely shape who you are for the rest of your life. Which is really not good when you consider that some scientists believe our personalities are set by as early as first grade.
Being a teenager fucking sucks even more, because:
-You can finally dress yourself, but you have no idea what that means and you will screw it up trying to fit in/not to fit in. How people dress in high school is the epitome of trying too hard in an attempt to emulate their friends, idols or role models.
-Your idols and role models are the worst. Seriously, there is no other way to put it. You will go through a very important developmental stage in your life trying to follow the footsteps of people that may not be the most respectable and reliable references for how to live.
-You will have friends, girlfriends, and other important people in your life that you will swear undying loyalty towards. You will sacrifice your health, options, and opportunities to strengthen these bonds, and most of them will be gone a few years after your graduate. These studies are all over the place, but most people choose to ignore them because we prefer to think of ourselves as paragons of unwavering friendship.
-You will have a variety of opinions and closely held beliefs that you will fight tooth and nail for. You will rant and rave and research your side of the story relentlessly to prove the things you know are cemented in cold, hard facts. People will come to recognize you as the guy/girl that's all about animal rights, atheism, libertarianism...and that you're really fucking annoying about it. What you don't and won't realize until it's too late is that even your opinions on opinions will change very rapidly over the next few years, and you're going to get all "cynical and skeptical and disillusioned." No, you're just embarrassed about the way you screamed the biological process of a decaying body to a young girl because she said she hoped her grandmother was in heaven.
So no, I don't miss being younger at all, and I wouldn't wanna go back and do any of it over. Being younger is like being a drug addict; you think it's a lot cooler than it actually is when it's happening, and you don't remember what was so bad about it until it's really all behind you. You're supposed to grow out of it. So please, stop romanticizing the past and just leave it where it belongs.