Past you isn’t the enemy. Past you is a teacher who left a lot of notes in the margins.

The version of you who made the bad call was working with less. Treating that person as an idiot costs you the only thing they left behind, which is a set of observations about what happens when you do that. Contempt for who you were is comfortable and entirely unproductive.

When an old decision comes back to you, ask what it was trying to solve. There was usually a real need underneath the poor method. Meet the need better this time rather than adding another round of judgement to it.