1001 - X?

So I vaguely remember selecting or deselecting genres at the start of this project. At the time, I was not aware of how this all works, I just figured I would not want opera (I don't remember what, if any I deselected, so no hate mail from violent opera fans please). Does this mean I can't do 1001? If so, am I on a track that leads to not adding my eventual user selected album? And if so, can I add back in anything I may have taken out?