I think I've thought of a way you can attempt to deconstruct this illusion.
If it really is extraordinarily robust and complete, then you should be able to lay out a brief summary of all of your decisions with large stakes, and a 1 sentence explanation of why you chose them.
If there are any obviously flawed statements then they should stand out as being less robust to other people.
If there are any large areas you just don't mention as a large stakes decision, that would probably also stand out as being less complete to other people.
If you find that you can't lay out the list because you find yourself thinking "Item 3: I choose to follow a career in... erm... hmm, that's a tricky one." Then you've solved it yourself and you don't even need other people. Similarly if you find yourself thinking "Wait, I don't even think I realized this thing was a big decision until I tried to generate this list." then you have solved it yourself.
If you find you need several sentences to justify a large stakes decision, that means you probably took longer than 5 seconds to think about it, and you may have solved it yourself again.
If everyone looks at your list and says "That really does sound robust and complete." then you have made a very impressive list of complete life decisions and answers, and in a very short time, which I would actually take as an indication you possess a great deal of general intelligence.
There are other possibilities, but that sounds like a good way of trying to start looking at the problem.
I can't come up with ANY items for the list. The only example you gave was choice of carrier, and the answer to that is "my health precludes having any kind of carrier or education any time soon, and by the time that changes all the relevant information to making the decision will be different".
It has been noticed since the time immemorial that cognitive biases have a nasty tendency of being invisible to self (note the proverbial log in one's eye). Uncovering their own blind spot is probably the hardest task for an aspired rationalist. EY and others have devoted a number of posts to this issue (e.g. the How To Actually Change Your Mind sequence), and I am wondering if it is bearing fruit for the LW participants.
To this end, I suggest that people post what they think their current rationality blind spot they are struggling with is (not the usual sweet success stories of "overcoming bias"), and let others comment on whether they agree or not, given their impressions of the person here and possibly in real life. My guess is that most of us would miss the mark widely (it's called a blind spot for a reason). Needless to say, if you post, you should expect to get crockered. Also needless to say, if you disagree with a person pointing out your bias, odds are that you are the one who is wrong.
(Who, me, go first? Oh, I have no biases, at least none that I can see.)