I enjoyed the film when I first watched it. I was assuming that it was mostly based on reality.
I become disappointed after I read John Nash's Wikipedia entry
His wife divorced him in 1963. In 1970, they started living together again "in a nonromantic relationship that resembled that of two unrelated housemates". She referred to him as her "boarder" and said they lived "like two distantly related individuals under one roof".
Knowing this torpedoes so much of what was portrayed in the film that the film leaves now leaves a bitter taste in my mouth.