Hindsight bias is a tendency to look back at past events and perceive events as more predictable then they actually were. For example, there are many ways a global pandemic could have played out, and there was a lot of uncertainty at the beginning. But now it would seem more predictable as there was no other probable course of action.
When looking at your own past decisions, it might seem that you made the right decisions but for the wrong reasons. We don't want to be critical of ourselves. And our brain takes a shortcut to avoid that and to explain it in a much easier way with the information of the outcome that you have now.
The only way to keep a check on this is to keep a record of how a decision was made. And evaluating them at a future point of time.