It's interesting that there are so many songs from the 'dark side', as the Beatles are so often associated with 'up' stuff, and Paul always points to how the songs are 'all about love or peace', but actually there's a lot more going on there!
Can't really think of anything new to add for myself, but I would say that my kids won't let me play Yesterday or Eleanor Rigby in the car - "Don't play the sad song!" they say! and I haven't let them hear Maxwell yet - it's the audio equivalent of a video nasty, all dressed up in a jolly singalong! They'd probably start singing it at school, and the teachers would pigeonhole them as mentally disturbed!
Just an after thought - I am the Walrus has a lot of unpleasant imagery, and John sings in quite a confrontational, 'I want to provoke a reaction from you' way, I think.