What’s the bands most technically impressive song?

A common critique toward Nirvana has always been regarding the technical simplicity behind every song (though there’s a lot of skill and beauty in said simplicity.) I believe I’ve heard every single is even in 4/4.

But out of curiosity, what are some of the songs you’d say are more technically impressive or unique, even if only by a slim margin? Could be regarding production, vocals, chord progressions (lol,) or lyrics. Is there any song that genuinely blindsides you?