Without attachment no expectations and without expectations no disappointment. No ups and downs of emotions. The life of a Sadhu.
Swami Ji writes about different philosophies, among them Patanjali's Yoga Sutras, that put emphasis on detachment, a full abstinence of any emotional or material bondage ro anybody or anything.
In his blog he talks about when detachment is good and necessary and when it is best, if you are a little bit attached, too.