Surprisingly, It has nothing to do with any lack of knowledge or poor skills, it looks more like going blind/deaf/numb for a short while... I should rather think a person who is capable of committing a series of blunders and then correcting themselves within just a few seconds is anything but mediocre.
Hm, it flatters to consider oneself something extraordinary but what actually lies behind it? How come knowing - and, mind! using it spontaneously - the correct something (word, phrase, number, fact, etc), someone will go astray every now and then? What might be going wrong in this head? And, I am pretty much sure it's not totally unique...
Could it be worthwhile to choose this topic for further research? It'll definitely lead to NLP... and might be a bit too hard to crack with all those blunders in mind..hm...
ps I do hate diary because they don't provide pasting from youtube....yuk, will have to do it later from here:
www.youtube.com/watch?v=XHAiYabOJWY&feature=g-h...
upd. done eventually