See, when you accept blame, the subconscious asks "why" and in turn answers the "how" which is the problem. The manifestation of this is the guilt you feel. And because that sucks, your subconscious again goes ahead to formulate an anti-again parameter so it doesn't happen again. What you may choose to call fixing the problem. Unfortunately, the past cannot be fixed, at least until they invent a time machine or discover a portal to the past. But basically it won't happen again.

Not accepting fault and the subsequent feelings of feeling awful about what happened means that you're okay that whatever happened did happen, thus you never really get to find out what's wrong with you. You don't get fixing.