I've never been scuba diving, though I imagine it can be quite the relaxing affair. Checking out the reefs, the fish, and just marveling at what is essentially a whole other world sounds pretty wonderful. It would stand to reason, then, that a game about scuba diving and taking pictures of the beautiful underwater scenery would be an equally relaxing affair.
Reef Shot definitely can be relaxing, in between all of the intrusive story bits and distracting objective markers. It wants to take you along for a ride, but in most cases, I'd rather be steering the wheel myself.