Picture the scene:-
Beautiful day in the Philippines, divers just finishing pre-dive checks, tightening straps, de-fogging masks etc. etc.
Dive guide gets everyone's attention "Hey guys, just a quick word before we jump in, I'd just like to point out that this is a pretty special dive for Larry here - it's dive number one thousand! Well done Larry!".
Larry's obviously a bit embarrassed by the attention, just mutters a shy thanks to all the nice people and does the crotch strap of his bp/w up and gives everyone a smile and says "Cheers, everyone. If we all make it back, I'll stand drinks in the bar tonight!"
Larry gives his buddy the final OK and they both roll backwards off the boat into the sea - a total of about 1 metre down.
Except that Larry doesn't make it.
Larry has managed to get the crotch strap around the permanent line that goes along the side of the boat for the divers to hold on to while equipment is being passed up or down.
Accordingly, he is now upside-down in the sea as far as his waist with his legs stuck out in the air, and trying desperately to figure out what the Hell is going on.
The buddy meanwhile has watched the debacle unfold, sees that Larry still has his reg in his mouth and is in no imminent danger of death, decides it would me much more fun to video his embarrassment.
Larry actually manages to get a grip on the situation, opens the waist release, drops into the sea, re-fixes equipment and carries on with the dive hoping that the video will never see the light of day.
It was a great dive, and yes, I'm Larry.