Couple of months ago I went to a popular South African scuba diving resort.
While diving, I saw some movement out of the corner of my eye. So I turned my head and looked straight into a wall of these guys:
Not thinking about it twice, I turned my camera sideways, fired off a shoot, and off I went on my mission without as much as looking back.
Pity I didn't stop to admire (and photograph) the scenery properly. Living inland I don't get to go diving in the sea that often, and it can be months between dives. Which is quite a long time if you wish to practice underwater photography.
Lesson - always take the time, and make the effort to stop and smell the roses (or the fish for that matter).