Horror Aficionados discussion

This movie starts out with a tall skinny awkward guy working at a telemarketing insurance company. He has one friend who is his direct supervisor. He eats outside alone, until a pretty red head sits next to him on the bench. They begin a strained relationship. In the mean time, main character is painting women's portraits. For some reason, he becomes paranoid that he is killing these women after painting them. He tries to talk to his friend,but he blows it off. The ending is really shocking, but I will not spoil it.

Am I missing something? What is the title of the movie, or are you asking for help in identifying it?

Title of movie. Please.