Good vs bad backlinks, what should we know?

I figure there are good and bad backlinks, ones that will help and others that won't do anything for you, or maybe hurt your site.

What should we know when it comes to good vs bad backlinks? I remember years ago when I had a site before, I used these sites where you can list your site on a database, creating backlinks all over the place. But I don't recall if it did anything, and I don't even know if it was safe to do.

What is the difference between good and bad backlinks?

I think good backlinks come from posting to sites in good standing. With what you mentioned, it sounds like it's be less helpful, but it might help in helping your site rank a bit quicker, but it's not guaranteed.

Your best bet is to focus on good quality backlinks if anything. Ones that don't go anywhere, are essentially a waste, at least imo.