I remember when I first heard Nirvana. I didn't really think anything of them one way or another. I wasn't too impressed.
The second time I listened to them though? They blew my mind. They're not really my style, which I think is why I didn't pay them much mind the first time around, but they're just the absolute perfect blend of solid and loose, polished and rough. It's no wonder why they're such a big influence on so many artists.