If this was the case, we would just be marrying anyone but we make choices depending on what we can accept to enter our lives. When you marry someone, their life choices, their problems and whatever they carry is now shared by you too. It affects you. I didn't say that you look for someone perfect, everyone has faults. Also you don't try becoming them but the view make you one. All I am saying is you need to know that their life is going to affect yours, accept it and be ready for what you are going to carry and assess whether the person is worth it other than getting married because of pressure and excitement.