So, not very surprisingly, I failed today. I could not get decent sleep last night and have been feeling like shit and quite tired all day.
As a result, after doing the basic stuff, the examiner left me close to an airport, and gave me a bunch of things to do to overload me (which is expected and part of the exercise). The point was to redirect me to a nearby airport but I was about 30 seconds late getting everything done and calling the tower, so in the end, I had just penetrated their airspace by the time I called them (i.e. too late). If I had been awake, I would
- have been just a bit faster and would have had had the problem, or
- realized that I was just a bit too close and turned around until I had time to call

Well, I did pass ground (i.e. required knowledge) with flying colors actually and I still passed a bunch of things in the flying exam, so I won't have to take those again.

Basically, I know that while I can be very smart, my mental abilities are very uneven, and go way down with lack of sleep (much faster than others) or other physical reasons. I failed to be in the top 1/10,000 students in France and had to settle with 1/1,000-ish mostly because of costly and punctual brain farts. This has plagued me my entire life, and obviously it comes up in flying.
My goal however is to have my skill level be high enough that I will manage to do the right thing even if I suddenly become very tired or otherwise start losing mental "sharpness" while in flight (I shouldn't have left otherwise) and get overloaded with bad situations on top of that.
I have achieved that for driving since I do an instruct for high performance and track driving: I can manoeuvre at high speed and in dicy conditions (like opposite lock countersteering if I oversteer in a turn due to water or oil), even if I'm not much awake, because I've trained enough that I can do it out cold. I have to reach the same level for flying.

In the meantime, I'm just frustrated because I learned nothing that I didn't already know today, nor will this piece of the test really help me in real life, nor will another 20 or 50 hours of training really help with what happened today.
Now, I'll just take the missing pieces until I pass them, which is mostly until I either get lucky or a decent night of sleep the prior night, but that kind of defeats the purpose of additional training when the training is already enough, and additional training will not really help improve my odds of passing next time.

Anyway, I should be able to try again in a couple of weeks and in the meantime, I Emailed the controller at Livermore Airport to explain what happened (not required, just a curtesy), and filed an FAA form about the airspace incursion (not requested, but it's good practise).
If you are curious, here's the form, ( NASA 277B PDF header and report ), which is just an excerpt of the report I sent to my instructors , although that's more technical and mostly for pilots