What is your favorite Led Zeppelin song?

With a catalogue as diverse and exceptional as Zeppelin, their music speaks to us all in such a different and personal way. They're the kind of band that gives a different favorite to every fan, so the question is really fun to ask.

For me, it's no question that it's Misty Mountain Hop, it's my favorite song period. I've associated a few instances of good luck in my life with this song. It's also a meaningful connection with my dad. It's just such a pure extraction of good feelings in audio form. Not only that, but the band actually messes up midway through! At around 2:16 they slightly lose time with one another and then catch up shortly after, and it's still the best to me.