The main problem with this movie is that there isn't a single element in it that doesn't demand you to suspend your disbelief to a level you just can't and don't want to maintain. If it were a wackier comedy, you could, but it's not. It tried to be a nice, sweet film with a gentle theme, but it came off as awkward, inconsistent, and hackneyed. It took an interesting premise (taking the phrase, "What, have you been living in a bomb shelter your whole life?" literally), and abused it silly until you just couldn't believe any part of it.