"Contemplative souls realize perfectly the nothingness of the things of this world, and so attach no great value to transitory matters. 

They may, it is true, experience a momentary feeling of vexation at some great wrong or severe trial. Immediately, however, reason comes to their aid, and overcomes the feeling of distress. Their chagrin is then completely dispersed by a joy that overwhelms them, when they see that Our Lord offers them this opportunity to gain more favors and eternal merits in one day than they could have earned by ten years of self-chosen trials."

~ St. Teresa of Avila

St. Teresa of Avila and St. John of the Cross, shown above in statues in Segovia, Spain, mastered the art of detaching themselves from earthly things - "transitory matters" - and so found great peace. They kept the eyes of the spirit focused on doing God's Will without being attached to what did or didn't happen in this life. God's Will is perfect, and in this they found their joy. And as she says above, they particularly exulted if they had some sacrifice to offer Him, that would bring Him pleasure, and gain merit for themselves in Heaven.

St. Teresa continues:

"While others seek gold and precious stones, these souls value and prize only the crosses, which they know will bring them true riches."