My friend had a purity ring that he got when he was still growing. He also had very bony fingers. He once had an accident that caused his knuckle to swell, the swelling took several months to heal. His knuckles grew but the tissue arround his knuckles did not. He was never able to get the ring off that finger, and he had it stuck on there even after he was married. It made me laugh. I think he eventually had a friend that he really trusted cut it with a dremel tool.
I think they're cool. Most of the dumb things we do require the use of our hands. And since it's on your hand, it's a good reminder that might make you think twice before doing something stupid. Just remember to take it off before doing any industrial work, or anything where you might injure your finger. That is unless you have a really trustworthy friend.