Blessed (well off) are they who mourn, for they shall be comforted.
Mourning is generally thought of as sadness over a situation or a condition which is often neither anticipated nor desired. In the context of Christ's Sermon on the Mount, he refers to the spiritual blessedness and happiness which is associated with having a right relationship with God.
Everything we experience - our life's circumstances; those which bring joy and laughter, sorrow and tears, the ones that test our strength, our patience and our endurance - are given to us by God for a purpose. When we understand that these circumstances are God-given opportunities through which we can grow in the virtues of: patience (in tough situations and even in those that may seem to be silly), justice (acting as a fair arbitrator perhaps between unhappy children, or family members), fortitude (possessing the strength to persevere in situations which may seem to have no resolution), and temperance (always acting in moderation).
All of life's experiences whether we mourn or smile are God-given opportunities to grow in his love. We must turn to him as our guiding advisor and place everything in his hands and in the hands of his mother, Mary.