I pray for our enemies as well as our friends. I pray for gays, atheists, the homeless, the rich the sick, the healthy, the suffering and the content.
I think I’ve found most peace in praying for those its hardest to pray for.
I don’t do that as much as I should, but I have, and it has indeed given me peace when I have been able to honestly pray for someone who I feel does not deserve my prayers, someone who has really wronged me or someone I love. It is an amazingly peace giving experience (but very difficult—I can’t always do it).
A college classmate used to snap, “You just made my prayer list” when anyone made her really mad ;-).