WALL-E is one of those movies where you just feel how much fun the people making it had while doing so. It’s the only 90 minutes movie I know having less then a approximate 500 words, at least spoken by humans. And, the WALL-E meets … serie on youtube is one of the best teasers ever.
If you think about it, the movie works in a quite predictable way: the lonely hero cleaning up a place everybody else deserted, meeting unexpectingly his heroine who first is very reluctant to his advances but finally falls in love with him when he saves the planet/humankind/etc. Nevertheless, it works and you come out of the cinema with a big smile and a feeling of happiness.