R&P: Can you pick one song for each decade that sums up the mood and feelings of the decade?

Explain how the song is relevent to the decade, how it influenced the decade and if it sounds like it could not have come from any other era.
Update: Props to anyone who attempts this question :)
Update 2: Smile

Great answer, I appreciate you taking time to go to the effort of giving examples and explanations about the artist and song.
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