to break the sentence down I do not want to (simple meaning of the sentence) I don't want to (as above but with shortened for typical speech) I just don't want to (the "just" means - only, absolutely, completely, totally, entirely, utterly, in every way, in every respect, in all respects) I just plain don't want to (the "plain" means - clearly or unequivocally, simply, easy to understand, simple) I absolutely and clearly do not want to (this might be easier to follow)

It means "Frankly speaking, I just simply don't want to (do something)"

Btw, is this from Hinton's "Rumble Fish"? :)