Haha, I love this:
“Bass playing is about the fuckin’ groove. Your band is gonna suck unless you and your drummer have got your shit going on."
2.5 expletives to get the point across, I dig it. 
Haha very funny thing in there:
“Learn from someone like John Paul Jones for dexterity, something like Immigrant Song, which he actually plays with a pick. Do those weird major runs with a minor seven during the build-up and learn how to play them fast.”
“weird major runs with a minor seven”… that’s a mixolydian scale, Duff! (those runs are at 0:44 on the studio track)
Is it still weird after being commonly used for (at least) hundreds of years? And it’s in, like, every blues tune ever? 