A lot of ppl are reblogging this saying they miss the pre timeskip characterization and he doesn't feel like him anymore he's not silly anymore etc. and what they're noticing is true but I'm not sure it's a writing flaw like everyone seems to think. I think actually Zoro's post timeskip behavior is a very realistic trauma response.
For one bright, shining moment in Zoro's life he wasn't alone. He was surrounded by family and love and laughter. And then he couldn't protect them. Even after wrecking his body in every possible way it wasn't enough. He lost them. Luffy, the man to whom he swore he'd never lose again, nearly died and Zoro wasn't there to help, because he did lose. Helplessly, brutally.
Then he spent the next two years doing nothing but fight and train and wonder if his friends were okay, aware even when he returned that he's still not the strongest fighter out there. That he still might fail and lose them all again if he's not careful. He had basically no social development at all during that time with only Mihawk and Perona to keep him company, both of whom are awkward loners themselves, really. All he had to occupy his mind with was grief, shame, and determination to be stronger.
So yeah he acts tough and stoic and he doesn't laugh as much anymore or goof off in the middle of fights because now he knows the cost. He knows what could be taken from him at any time. He is not going to let his guard down. If keeping his family safe and together means he doesn't get to feel as carefree anymore, he'll choose that in an instant. He will always choose the option where he takes on a burden and carries it as well as he can so that no one else has to.
In short, he's terrified. This is how Zoro acts when he's afraid and refusing to show it. And I don't think his characterization will stay this way forever. I think sooner or later he's going to break.
