If I asked you, "are you an accountable person?" You'd say "yes!" If you asked me, I'd say the same. In fact, if you asked the least accountable person you know the same question, they would likely reply in the shocked, and slightly put out, affirmative.
We all think we (ourselves) are accountable people. And we are. Sometimes. It's that 'sometimes,' that makes us not accountable people overall.