Considering that just watching this video gave me an adrenaline rush, I think I'm OK without ever going cage diving with sharks.
YouTube user/brave person Hillary Rae uploaded this video of her cage diving experience on a trip in South Africa, when the cage she and her friend were in got attacked by an 11.5 foot Great White shark. Half of that length is the height of Robert Downey Jr., so this shark attack was basically like being attacked by two RDJs, if RDJ had monstrous teeth and could breathe underwater and very easily kill you (and not just with his sweet bedroom eyes).
According to Rae, after the shark was done with the cage, "The round buoy attached to the side of the cage was bent in half. Some of the lining of the outside blue barrier bar was bitten through as well."
Nope. No. No thank you. Yes, I know that swimming with sharks in a dive cage is safe, and no, I still don't want to do it. Even if it is just two Robert Downey Jrs.