It was her idea to get certified for scuba diving. Prior to her suggestion, I had never really thought about it, one way or the other. I was not opposed to the idea, nor was I particularly excited about it. She wanted to do it on the trip to Mexico, and I wanted to go on the trip. So, I got certified. The first part of getting certified to dive is classroom stuff, followed by some dives in the pool. Those were fine--the physics and biology of diving is interesting, and I didn't have too much trouble with the skills (one woman in our group panicked immediately upon going under water in the pool--claustrophobia). Getting into the ocean, on the other hand, was a different matter. Twenty minutes into the first dive and I was hooked forever. I just knew it. It's a physical skill, but it is also relaxing. There is an element of being alone, just you and the sound of your breathing, but it is an activity you do with other people--you an...