Hope for the best and prepare for the worst
Hope for the best and prepare for the worst,and Hope for the best but expect the worst.
Prov. You should have a positive attitude, but make sure you are ready for disaster. While my father was in the hospital after his heart attack, we hoped for the best and prepared for the worst. When you study for a major exam, hope for the best but expect the worst. Don't make yourself anxious worrying that it will be too difficult, but review as if you expect the exam to be extremely hard.