What is a DM? Well, could be a DM or instructor who acts as a guide.
Main thing? Loves diving, is willing to put up with an incredible amount of crap and abuse from people, loves diving, great people skills, loves diving, has the ability and knack to find the small stuff, loves diving, can keep track of people and ferret out skill levels in a short amount of time, loves diving, and most importantly can and will work for crap wages even with a smile on their face when putting up with abuse from people who think they know everything!!!!! :11:
(Did i mention i was a full time dive guide for 5 years...)