I feel there lays the whole difference between why Taani grew up to be such a happy, chirpy, full of life girl and even now is strong enough that despite being hurt in love she is able to move on in life strongly while still loving Anurag. She had a mother to take care off, she was never left alone to be frustrated and deal with her fears and frustrations all by herself. A mother's love and attention is what can make or break a child. Taani had a mother like Laboni, no matter whether she proved a mother to Anurag or not, she has been an excellent mother to Taani, in bringing her up, in making her strong enough to face what may come in life.
On the other hand Anurag was left alone at an age that can make or break you as a human being that determines your future, your morals, your values. At an age where you learn what the world is and what you have to do to face it successfully. His family was taken away from him, his best friend with whom he shared everything with was taken away from him and he was left into a whole new stranger world with his frustration and fears and was asked to deal with them on his own. No wonder he shut himself to all emotions, built a hard shell around him so that no one can see inside and notice how broken a human being he is. There was no one to tell him the difference between right and wrong in a country whose culture and life style was so very different from his own. He had no guidance, no one around to share his pain or fears with, end result had to be what Anurag Ganguly is today, obsessed, possessive, hard and i feel after yesterday a bit psycho too. Saddest part is he will be the one who will suffer the most, for what is not even his fault. There was no one to understand him 8 years back and there is no one to understand and see through him even today.