Is it a reason for all worries? Or is it a reason for all successes? It may be true but anticipations keeps us always in tension. Either we anticipate a success or a failure, our mind will be eager to know the result and develops tension within till the last minute.
Once the result is known the reaction is relative to the weight of the anticipation. Positive anticipation with a negative result gives lot of disappointment. Negative anticipation with positive result is a surprise and excitement. Both feelings are not good for health, when they are of high degree.
So we can anticipate any thing as we wish but it should always be scientific and calculative to match with the final result. Simply to say, I should not anticipate a first rank in the examination when I have not at all opened the subject book and engaged in other activities.