"What Makes You Think You're the One" (Fleetwood Mac)

I like Lindsey Buckingham best when he has the forum and freedom to be as weird and experimental as he wants to be.  Sure, it takes skill and talent to write/produce a pop song; but it takes guts to push your music so far from center that it teeters on the brink of madness.
Although his more recent solo albums thoroughly showcase his experimental side (1997's Under the Skin remains a personal favorite of mine), Fleetwood Mac's Tusk (1979) probably was the first inkling that he was more than just Stevie Nicks's arranger.  Every one of his tracks on the album have this hyperactive, New Wave-y urgency that signal discontentment with being a "soft rock" star.
A good example is the track "What Makes You Think You're the One."  Not unlike the acerbic "Go Your Own Way," it's a song about Buckingham's strange and complicated relationship with Nicks.  Only this time around, he's not willing to give her his world.  In fact, he's saying that he's tired of having to prop her up, musically and emotionally.
Not only does Buckingham sound fantastically unhinged, singing like a madman over his own piano and guitar accompaniment, but Mick Fleetwood beats his drums like they insulted his mother.  It's so primal and anti-pop that you might be tempted to check the album cover to make sure you're actually listening to Fleetwood Mac.  (Or, better yet, it's a reminder that Buckingham and the Mac are more than just the sum of their Top 40 hits.)