The premise was interesting, but I found the film gimmicky, self-conscious and tedious.
Interestingly, a couple of years after the film came out, I met a woman who had suffered a head injury and basically lived this man’s life, (albeit maybe not quite as extreme). She navigated through the world – pretty successfully – with the help of her family, by writing on herself, and mostly “post-its”. Maybe her brain was starting to establish new neural pathways for her most repeated tasks, or something. But, it did cause difficulty in her family relationships, and in her work as a liturgist, she had a hard time connecting music with the rites/services in her church, so that music became just a series of notes, rather than something with a sacred component. This was the saddest thing of all for her.