More optimistic than book (spoilers possible)?

I read the book two years ago, I saw the movie yesterday on my DVD. I loved both, though book is obviously fuller and there are many subplots omitted in the movie. However, I had completely different thoughts after watching yesterday than after reading. The book left me feeling rather depressed (everybody dying in the end - I still can't figure out what was the purpose of it, I also don't know if Garp's death was necessary). The movie was somehow lighter in tone, and the message (at least I understood it that way) was something like "you should never give up, no matter what life brings". I also like to think that he didn't die in the end and they lived happily ever after - there was enough sadness in their lives. Maybe I'm stupid but I like it more than the ending in the book. Does anybody else feel that way? What do you think?