9) 'When I'm Sixty-Four'
From 'Sgt. Pepper's Lonely Hearts Club Band' (1967)

According to the story, McCartney wrote this song when was 16 and forgot about until his father turned 64, which happened to be as the Beatles were recording 'Sgt. Pepper's Lonely Hearts Club Band.'

Paul often gets mocked (sometimes justifiably so) for his nostalgic side, but here's one occasion where it works to his advantage. Beneath the vaudeville music lies a deceptively innovative lyric. He's trying to convince his new girlfriend of his worthiness by painting a scenario of what their life will be like in the future. It won't always be easy ("we shall scrimp and save") but spending your last years working in the garden and playing with our grandchildren make it all worthwhile.

Listen to 'When I'm Sixty-Four' by the Beatles

Next: 'If I Fell'