Every athlete will have experienced the day where, from the moment you wake up, each smallest thing that happens seems designed to throw you off, by means of frustration or distraction.
Whether it's your mood which throws a dark light on circumstances, or an actual sequence of negative events, the reaction is the same: that scared and lazy sluggard who is normally regulated to a soundproof corner of our minds, escapes to niggle and gnaw at our resolve.
This happened to me the day I was to attempt 86m.
I started the day in a foul mood, and it seemed everything conspired to keep me in it. I had to find someone to fill a vacancy in safety freedivers, then was left temporarily without a ride down to the Blue Hole (my truck was being used as the emergency vehicle). While I was breathing up I noticed the velcro patch on my leg (where I attach the tag) was coming unstuck, so I borrowed a knife to cut half of it off. The bad run continued right up to the last moment: I missed the timekeeper's minute call, swallowed some of my air as I rolled over into the duck dive, and realised I had started the dive slightly hypocapnic...
These are all reasons that we sometimes give ourselves for aborting a dive, and the lazy/scared voice will be standing on a pulpit ready to take command.
At this point training and a long background of deep dives pays off: you must be able to turn off the conscious mind and operate completely on autopilot, confident in the actions and contingent decisions you have programmed into your unconscious. If you cannot turn off the rational, analytical mind then neither will you be able to turn off the pestering, pessimistic voice that shadows it - he will follow you all the way down, 'blah-blah-blahing' until you either turn early or doom the dive through agitation and increased O2 consumption.
We do however need to be able to distinguish between trivial detail (you cut your finger and the salt water makes it sting) and conditions that actually impact on performance (you have a wry neck and can't relax at all in the breathe-up).
As I settled into the freefall on my way to 86m I felt the bad energy that had surrounded my preparation slip away - it was superficial and therefore stayed on the surface. Beneath everything else I knew little had happened which would have impacted my physiological state. Perhaps I breathed up slightly too much (making me a shade hypocapnic), but my blood pressure has been good recently, and I would still be capable of this depth.
When I turned at the bottom I concentrated, as always, on counting my ascent strokes: 29 for this depth (2 extra because of the lanyard).
Thoughts, both negative - "you're not going to make it!" - and positive - "if you make it you'll have a new world record!" - try to clamber up into your attention, but the trick is to be bored with them before they even begin.
Whatever it is it doesn't matter now - the dive has already been decided long ago...
The bonus is that I have never been so happy at the conclusion of a world record, precisely because I had to overcome adversary (the hardest kind - the internal adversary) in order to achieve it.
The next day's FIM attempt to 108m was very similar. An athlete's bad blackout shortly before my dive unearthed the gloomy foreboding. I told myself tha
t the dive revolved around equalisation: if I was able to maintain relaxation while equalising to the plate it would reduce narcosis and promote the dive reflex. As it happens I was so focussed on equalisation that I ended up with a mouthful of air at 108m. When I turned to ascend I instinctively purged this air from my cheeks (about 75ml, which at that depth is almost 10% of my total lung volume), and this might have contributed to the dive being harder than the previous 107m.
If you are able to overcome bad initial circumstances and slip back into that passive and detached state that accompanies a perfect dive then the effect on your future dives is paramount: confidence blooms and your depth in competition rises to meet that reached in training. The reverse is also true. Every time you succumb to that despairing voice you will fuel your own fussiness and superstition.
Learn to distinguish between instinct and anxiety. The more often you get it right the deeper you will bury the sluggard, until his complaining voice will be shut off for good. Confidence comes from beating the inner adversary.