The Yismach Moshe zt’l said that when he was young, he heard from tzaddikim that when one says viduy he should think: a time will come when I will stand before the beis din in heaven (the Heavenly court). I will be dressed in a tallis and a kittel, and I will say viduy like I’m saying now, but then it won’t help me. But now I can fix everything with my viduy…”