Let me ask a counter-question: If a website is bad quality, why would you link it at all in the first place? (Barring that you want to give a negative example ...)
Imo the use of "nofollow" should be clearly restricted to paid links and ok, maybe forum/comment links. It is somewhat idiotic to slap a "do not follow or count this link" on a link you set yourself. A link you set yourself with a purpose, because it is relevant to the topic, gives additional information etc. If I was a search engine, I'd really consider NOT honoring the nofollow tag when somebody puts it on every link. To me it also feels somewhat dishonest: You point to a good ressource and also say "but do not give them any credit for me linking and recommending it!". Never mind the human visitor does not see or feel the nofollow in any way at all... and when user signals get more and more important, why exactly should search engines (continue to) honor something that has no bearing on human users at all?
In short: IMO nofollow belongs on paid links and on links the website owner has no way to endorse/influence (comments &c.) if necessary. If you set links yourself, it should be a normal follow link. If you want to put nofollow on it, question why you want to set this link in the first place.
Nico