The last one, sort of. It usually takes the form of, "You don't want THAT to be in your dream log, do you? You'd better skip it just this once. It's okay, you'll write down the next one. That dream sucked anyway, and you're already forgetting it besides. Also don't you have better things to do?"

All, of course, with the low-level realization that I know all of this is bullshit but I obey it anyway.