I think the point is that stimuli and physical conditions still create certain emotional responses in you. You may or not be aware of these responses or contributing factors, but most everyone is effected by them. Stick someone in a dark room for weeks and they're not going to be very happy no matter how aware or unaware they are of their surroundings.

If it's a specific case of ignorance is bliss then I agree, remain ignorant. Otherwise, it's good to know things that cause problems so you can fix them.