Taking responsibility sucks. Really it does. Obviously not for the good things, like baking a cake or writing a novel. But when things go to shit; then things go to shit. As kids we're sheltered from it by our parents: "Oh they're young, young people make mistakes." But when you come out into the real world, you have to learn to take responsibility.
People still don't want to though. They could be 5 or 50, some people will try and shove the blame onto somebody else, on their nature, on the universe. Whatever it is, it isn't them. But to be perfectly honest, you shouldn't do that. You cannot do that.
Yeah, you feel your insides twisting themselves into a ball of mush and you just want to puke and cry and scream all at the very same time. You are just ashamed that you fucked up so unbelievably much. All you want to do is bury your head in some long ago, warm time when everything was ok. But we can't do that anymore: You messed up, deal with it!
I don't know if it's a part of going up, but for me it's apart of becoming a better human being which every person should strive to do. But that's not all of it though. You can't just take responsibility for a mistake, or poor decision. People say they're sorry all the time. You have to also change your behavior. Realize you did wrong, take responsibility and then figure out a way to change. You messed up, now how are you gonna fix it and make sure it doesn't happen again. That it what truly taking responsibility means.
It's the hardest thing in the world to realize you made a mistake, but it's even harder still to take responsibility and change your character accordingly.