This film falls into the genre of over-the-top movie fairytale. It's meant to be unrealistic and cartoonish, and it beats you over the head with symbolism. To me this film did only a mediocre job of pulling this off this genre. The movie starts off firmly establishing the cartoon style with the grey masses marching into work: the 'Home of the Rectal Probe'. But the film did not maintain this style and visual starkness. About a third of the way in, it degenerates to standard B-minus grade camp. Part of the problem, I think was the casting of Tom Hanks. He just wasn't able to do 'cartoon' very convincingly. Too much of his 'everyman' screen persona came through and also he's got a lot of mannerisms that he used in Big, which I found annoyingly familar. Meg Ryan played 3 characters. You won't recognize her as the first two. I had to check the listing to believe that she was the first woman. In these first 2 roles, she's pretty good as cartoon comic characters. But the last character is stock "Meg Ryan playing the love-interest in a romantic comedy". I've seen this character in at least 5 films now. Boring. It was especially annoying since after the first 2 characters, one realizes that she can protray different characters.
Summary: I personally cannot imagine any reason for someone to see this movie except that they are interested in Tom Hanks and Meg Ryan. Even then, it seemed mostly interesting to see how Hanks has modified his acting over time. About 3 years after this film, he finally got rid of most of his early stock mannerisms -- something that anyone aiming to be a character actor has to do. But that said, there are lots of people who find deep meaning in this film, and this film has a cult following of sorts. People write essays on the symbolism of this film and make websites dedicated to this film -- I guess there are a lot of people who empathize with Joe's mind-numbing boring job and 'spiritual' awakening.