I found this on the net:

This is a little bit from Come as You Are: The Story of Nirvana by Michael Azerrad about Dinosaur Jr. I thought it was nice and wanted to share it.

…Kurt laughs when it’s suggested that his natural state is one of agitation.
Not unlike the music of Dinosaur Jr’s J Mascis, whose laid-back
vocal persona exists against a constant backdrop of angry, teeming
distortion. "That’s not really a character he plays- he is that per-
son," says Kurt. "God, I wish I could get away with that because I’ve
always thought I was really close to J Mascis as a person, personality-
wise- just quiet and talking with a cigarette voice, but I couldn’t sing
like that. I had a different side to me that’s really hyperactive."
Like Mascis, Kurt appears passive, yet both control virtually
every aspect of their band’s music and image…