My wife and I do safety / emergency drills almost every time we exit. Lights out, air shares, valve shut off drills, lost line, lost diver... It's a big list.
We've had a few issues under water, mostly equipment problems. A couple of regulators with leaking high pressure seats, a blown pressure gauge o-ring, a couple of flooded flashlights, one broken fin strap, and one canister light that continually shut itself off. Really nothing to get worked up over, but enough to turn the dives.
Oh yeah, add about 20 fouled reels to that list
