I've gots lots of stories, some good, some bad.
Good example, 2-3 weeks ago, our corps went out on an abseiling ex, with some of the newest recruits. As some of you may know, there is always gonna be a cadet that either doesn't want to go down, or gets all hooked up, gets to the edge, and then quits. Well, we had one new recruit, who decided to get hooked up and quit..... 4 times in a row.
On my second "graduation dive" after I got my Open Water Diver certification, we went and dove the Chippawa river in Niagra Falls. The first dive was kinds crappy, I only saw rocks, and golf balls, and the current was really slow, because the power generator at the end of the river had slowed the current for some reason, so I had to fin it down the river. The second dive, however, was far more intersting. The current had picked up, a LOT. By the time I got to the bottom, we had reached the remains of an old demolished bridge. This is pretty dangerous, you're clipping along pretty fast, and since the visibility wasn't that great, you only had about 1 second to avoid something one you saw it. My and my buddy were connected via a buddy line, a piece of rope about 6 feet long tied to out buoyancy compensators. We had just avoided a huge concrete pillar, and both looking down to make sure we didn't hit any metal or rocks, when a metal gurter, sticking straight up popped out of nowhere. Right in between me and my buddy, with our buddy line right in the middle. You could probably imagine what would happen next, but the strong current, and the 100 or so pounds of dive gear we had on made it extremely difficult to get out of this. I couldn't go back upstream, and get around this gurter, and I couldn't surface, because there's tons of boat traffic around, so I ended up pulling out my knife and cutting the line. That was pretty scary when I was happening, but now that I think about it, it's pretty funny.