So tonight I'm driving home from church and I see three guys on the side of the road. Their car has hazards on and one is starting to walk. They're probably mid-20s, all a bit rough-looking (although it's hard to look tough when you're shivering in 35-degree rain).
I pulled over and discovered they were out of gas. I offered to drive one to the nearest station and he agreed. On the way there he gets more and more nervous... first he tells me he's going to put $10 in my tank for me, which I decline. Then he says he'll just leave me the cash, which I also decline. By the time we got back to his car he'd made the offer three more times.
As we pulled up, I said to him "I'm going to be praying for you on the way home. What should I be praying for?" The dude freaked and jumped out of the car almost before I was stopped. He mumbled "safe trip" as he was going, which either meant he wanted me to pray for him to have a safe trip or he was wishing me one.
So on the way home I prayed that he'd have a safe trip home, and that God would handle the follow-up (since I'd probably never see him again). After I prayed, though, I laughed and laughed and laughed. "Free" really freaks people out. It's a scary thing to be in somebody else's debt... to have the slate wiped clean when you'd rather pay back.
Grace isn't cheap, but it's free. And fun.