Oh gosh yes! Especially young characters it is amazing how they take a life of their own and shape themselves during the rps with others as they grow! Many babies of mine have grown up into adults that are quite a bit different from what I expected at first, and even adult characters often things happen in their story that makes them take sudden turns and handle things in a way I didnt expect until I am there writing the reply! It is one of my favorite parts of rping for sure, I think it means you really understand the personality you have created for them if you can get that much into their character that their mind and their will overpowers whatever it was you personally wanted for them.