We should share our joys and sorrows with our Friends and near and dear ones, whom one trusts that he/she will not disclose it to any body else. This way we could be able to know the view point of others on the matter. Suppose if we are suspicious of some thing and tend to get frightened on its disclosure or may harm some body. Then upon discussion and various view points we can arrive at some conclusive decision and our fears may run away or we may correct the situation as the case may be.
Since at time we have limitations in our knowledge and asking guidance or expertise or having a discussion on the matter may put our suspicions at bay and supposedly we tend to arrive at some concrete decision.
Likewise we should also share our joys with others and it increases the level of happiness upon sharing.