Real diving mishaps please

[LKunze]

Good topic.  I'll bite first and swallow my pride to admit my dumb mistake.  This occurred a few years ago on a dive with Dan G and Jason Baker at Wazee.  I wasn't technically completely out of air so to speak, just didn't have my tank valve turned on all the way.  I turned on the tank while setting up my gear but didn't end up going in the water for another hour or so.  I must have turned the tank valve off for some reason but not off all the way.  When I was ready to get in the water I made the mistake of not checking the valve pre-dive.  Instead,  I just purged the reg and breathed off of it at the surface and confirmed the pressure gauge was reading fine and my reg was working fine.  It wasn't until I got down to about 130 feet that my reg started breathing really hard all of the sudden.  It wasn't gradual, it was instant.  I signaled OOA to Dan G and he donated me his primary on long hose, and we did a safe ascent to 100 feet.  Once there at the ascent line I put my reg back in and it was breathing fine and it then dawned on me what the problem was.  I wrote Jason Baker a note on my wetnotes to check my tank valve (I was diving a single 119 at the time and couldn't reach the valve by myself like I can in my doubles).  He confirmed that my valve was only on about 1/4 turn if that. :-[  He wrote me a deserving note back which read STROKE!  Anyway...lesson learned.  There was no panic by myself or Dan in this incident.  I had practiced OOA drills several times prior to this incident so was prepared.
Also, I did get hung up a little in fishing line a couple times in Perch Lake and in Ore Be Gone.  Pretty easy to cut through it with the knife though.