The writers could have written the hell out of Bob Biswas's life as there was no such mention in kahani. He was just a serial killer with a unique style of committing murders.
But look this is what the writers came up with.
1. The killer lost his memories in an accident ( obviously 😓 ).
2. He was in coma for 8 years. ( Yes that is true !! ) and came out of coma absolutely healthy , fit and with a big fluffy tummy .
3. His wife tried her level best to keep things exactly like before in order to hasten his memories to come back. And she did almost too perfectly without any human emotion fitting for that situation. She was like ' koi bath nahi ap aa gaye coma se 8 saal badh now let's all live our life like before'.
4. Then there was usual predictable story line with a lot of unanswered quarries.
Eventually you will fail to have a fair perception of the character Bob Biswas ( same like at end of kahani ). For example,
For whome he was actually working for ?
He had a fantacy for his friend's wife and he killed his friend for this. Eventually getting married with his friend's wife. At last he ends up being a faithful and loyal husband and father. That is too much of stretching for someone who is normal and now changed ( may be due to memory loss 🙄) or someone who is psychogically ill.
There were many such things remained unanswered and wierd in many ways. Overall this movie suffered for poor script and story writing inspite of some good acting.