We will never achieve anything of any consequence in our lives by looking backwards!
We certainly don't see fighter pilots looking into the rear-view mirror too often because they're moving at rapid speed that it might result in their death if they did look back too much.
Although it makes a whole lot of sense not to look backwards, unless just for a moment, most people, if they were aware, look backwards “consistently and habitually.”
When you look backwards and worry about past experiences that you no longer can change, you empower them and keep them alive in the deep recesses of your mind.
Practicing mentally activating past events, whether real or not, true or not, stimulate the emotional side of your mind, the subconscious mind, which it accepts as being present and true.
However, understand that the greatest achievers of today and yesterday always look to the future and their next stepping stone and don't stress over the something already past and dead.
They are forever considering what if, what could be and what potentialities are to come, rather than already what was, and then they move ahead with speed of implementation by taking immediate action to bring their ideas to life. Thoughts without action is just wishful thinking!