"There are some benefits [to amnesia] however. There is no such thing as a repeat on TV and every joke is funny..." (http://www.dailymail.co.uk/health/article-1285535/Two-car-crashes-leave-Michelle-Philpots-24-hour-memory.html)
Adam Sandler plays Henry, a veterinarian from Hawaii who avoids commitment until he meets a woman named Lucy. The two fall in love, but Lucy, who has no short term memory due to a car accident, keeps forgetting who he is.
Henry, along with Lucy's father and brother, plays a charade whereby they pretend it is always October 13, the last day in her memory bank. Each day, Lucy is handed the newspaper with that date; she watches the Vikings football game; and she uses a full bottle of shampoo (refilled by her brother). And each day, she has another "first date" with Henry.
The charade works until Lucy is ticketed by a police officer for having an outdated licence sticker. Henry and her family have to come clean. He makes her a video which she plays every morning to remind her about what has transpired in her life since October 13 (https://en.wikipedia.org/wiki/50_First_Dates).
Lucy is based on Michelle Philpots, a Lincolnshire woman who suffered two accidents, one on a motorbike, one in a car. Just as Lucy relied on the video to fill in the missing years of her memory bank, Michelle relies on hundreds of post-its on her wall, dozens of reminders on her mobile phone and several photographs sitting in frames. Her husband has shown tremendous patience faced with her memory loss, called Anterograde amnesia.
Michelle explains that her amnesia is not completely negative. "There are some benefits, however. There is no such thing as a repeat on TV and every joke is funny..."