Funny that so many people find it so hard to enjoy a movie that told you up front that it was a light a feel good movie. Yesterday was fun, had you smiling, had you moving your feet to the remade Beatles songs, had you chuckle at the mad cap characters and their relationships. And the love story...spoiler alert at the end of this sentence...you knew the leads would get together by the end, and you could not help to feel happy, upbeat.
If you go into the movie Yesterday expecting heavy drama or feel some philosophical statements or moods, then please go to another movie and be miserable in that theater.
If you want to smile and remember the magic of the Beatles, and have fun with the concept of an alternate world without the Fab Four and cozy characters who entertain you, the you will enjoy Yesterday, and you will keep smiling after the movie is over.