From a Zen Buddhism point of view, Jennifer posted a comment at Abyssal Mind that accurately describes what Christian mystics call detachment. Her favorite saying from Buddha is:
Suffering is wishing things were other than they are.
Very good point! She goes on to say,
Remembering this phrase during tough times has definitely helped me to let go of the need to control situations and to upgrade my ‘attachments’ to ‘preferences.’
I would add that one needs to keep this in mind also when times are going well.