Imagine flying to your destination airport only to discover the only runway is closed or the VOR the instrument approach is based on is out of service. Surprise! Now what? Is there anyway you could have prevented this surprise in the first place? Sure! Check the NOTAMs. Ask your self how will the NOTAMs change today flight.
Now imagine getting yourself within 5 to 10 miles of destination. As you level off from your descent and add power the engine doesn't respond to the throttle input. You run though the engine failure checklist and to your horror you discover you're out of fuel. Why did that happen? Was it because you miss calculated the fuel burn, not lean the engine(s) or not check the fuel caps after the last refueling. Statically fuel starvation and fuel mismanagement are the number one reason for engine failure. Have you ever compared what the airplane actually burned versus what you calculated for the flight?
Its a -30C day in January and you're shooting the ILS 18 approach in LSE. Three quarters down the ILS ATC calls you and say N1234 Low altitude alert, check altitude........... Why did that just happen? How could you have prevented that from happening? Clue. What does the snowflake mean on the IAP? What do you do with that knowelege?
Folks, Knowledge is power! Not only will it help you pass a check ride but it will keep you from being an accident statistic.