Different people brings out the different characteristics in the same individual. Maybe that is why some people observe that when someone is with another person, he/she behaves different as compared to when he or she is alone with friends, or in a previous relationship etc.. It may not be that the person whom you are with changed you. I think of it more like a magnifying glass, but different people magnify different aspects of you. It may be possible, but I don't know if it is desired, for somebody to stay exactly the same, before being in a relationship and while in a relationship. Interactions with people are supposed to affect us to a certain extent, but of course we can't let people walk all over our lives and make us behave 180 degrees differently, that would seem unnatural.

With this in mind, I guess the person I want to be with will be someone who can bring out the best in me. And even more so better if I can do the same for her as well. After all why affect each other for the worse right.