When product teams work in sprints, a common practice is to undertake a sprint retrospective at the end of each sprint, where the team discusses what went well, what didn't and the things they'd like to start or stop doing as they go forward. 

With each iteration, the team that works together learns to work better together and improve the quality of their outputs and the velocity at which they deliver them.

Retrospection helps us acknowledge how things are right now.

It helps us understand why they are the way they are.

It helps us come up with changes we want to make immediately to our actions that will help us steer ourselves in the direction we want to head in.

Failing to retrospect, on the other hand, is equivalent to driving aimlessly. 

Sure, you'll still watch out for what's on the road and not get into an accident. But, you'll have no clue about where you'll end up.