They are very friendly I think. There was a special one that lived off a certain reef and divers would visit it all the time. It had a name and was very special.
In the July issue of Sport Diver magazine there's a picture of a Napolean wrasse visiting a SCUBA diver. It says the photo was taken on a reef in Tahiti.
Saltwater has some crazy monsters! That "planet earth" show that aired on the Discovery channel said that there are some species of manta rays that get 27 feet accross!