Nirvana wasn't my favorite band by a long shot when I first started playing guitar, but they were definitely the biggest factor in me starting to play guitar. And as I mentioned before (whether in this thread or another one somewhat recently), they were how I first taught myself to play guitar and sing at the same time, which was at a time where I didn't rally listen to them that much anymore. And I've met tons of people who Nirvana was also their main reason for starting to learn guitar, bass, drums, and so on.
I grew up listening to rock, but Kurt Cobain was the reason I picked up a guitar.
"They can kill you, but the legalities of eating you are a bit dicier." - David Foster Wallace