I think to some extent acceptance just means understanding your situation is different. When you first get the injury, you are typically in denial about the severity, then like most you go through anger until you eventually reach acceptance. That doesn't have to be calm, or ok with it, it just means that you've moved past the constant bargaining. I had another long term injury prior to the TBI that drastically reduced my quality of life and I would never say I was ever ok with it. But I accepted it as a slight limitation.