Oh look, a Kubrick article on NFS.
1) Don't buy that crap one seen in the photo.
2) Don't read this site full of absolutely terrible guidance (see other comments below)
...and this has what to do with teaching me how to make a film?
Maybe Ryan Koo needs to come back and explain exactly what this website was set up to do.
Coincidentally, this is the 93rd Kubrick article you have posted this month
Bickle's actions are caused through bitterness and jealously.
He originally plans to assassinate Pallantine so that people will take notice of him - to disrupt privileged lives (he would see that everyone who gets to live a normal life without constant mental anguish is privileged).
Iris is a saint on a pedestal - someone with who he can make some sense out of his place on earth. He can do something good, and make a difference.
Plus his actions would mean he no longer has to live with the mental pain once completed.
It's a childlike understanding of redemption in the character.
The first half of the film cements how impossible he finds fitting into an everyday person's life. His condition doesn't let him plan, or see a place for himself in the future.
The second half of the film is him looking for an out. Just a way to get off this earth.
It doesn't look better. It looks plain weird.