It requires a self-reflection and a claiming, not just a reacting, and that takes discipline. Reactions happen automatically, that is their nature. If not met with discipline they just continue as chain reactions. They ask nothing of us. Even infants can react.
Automatic responses are just that, automatic.
Accountability is a deliberate, thoughtful response. To be accountable we must be reflective and deliberate. We must conduct an honest search to discover the truth about what was and is going on for us and why. To be accountable we must confront our reactions and discipline ourselves to search and try to discover, understand, and claim what we've said or done, not just react. It takes courage to be accountable because we have to be honest and claim our part in whatever we said or did that we are being confronted about, either by ourselves or by another.