First, it's worth making clear that no prediction about anyone else or yourself (even if you do it for yourself) is set in stone because, at any moment, we have the potential to completely change the thoughts we dominantly think. See When fortune-telling or predictions come true, do the results come about because of the Law of Attraction?

But, aside from that, and to answer your question, it's the same reason that the solution to other people's problems are usually easy to see, whereas the solution to your own problems are usually difficult to see.

You have a greater level of "detachment" from the issue when you are dealing with others, instead of dealing with yourself.

You see this happen on IQ regularly. It's usually obvious to others where someone else is vibrating but they just cannot seem to see it themselves because they are so immersed in their own issues.

The same thing happens for "vibrational readers" too. In that category, I would put psychics, clairvoyants, channellers, and anyone else that picks up intuitive information.

Even vastly-experienced channellers, for example, say they find it much, much easier to provide channellings for others than for themselves.

That's the high-level explanation but you seem to like details :) ...so here is the more technical explanation...

Basically, you cannot "Ask" and "Allow" at the exact same time

(Step 1 & Step 3 are different)

They are different vibrational states. One is the vibration of the "problem" and one is the vibration of the "solution" and you have to be in one or the other at any particular time, otherwise you would not be able to differentiate a problem from a solution. See How do I channel experience of meditation to art?

Some highly-gifted vibrational readers are able to switch quickly from one state to the other but even they cannot achieve both states simultaneously...at least from a 3D physical perspective.

I used to be good friends with a guy who was highly-gifted psychically. When he had to provide information to others, he would be flooded with impressions that would easily flow off his tongue. But when it came to himself, he would be stuck.

I remember him coming around on occasion and me having to sit there asking him questions about himself that he had given to me to ask a few minutes earlier. It was because it was much easier for him to "receive" if someone else was asking his own questions :)

But even if you are able to "receive" information for yourself using tricks like this, you still have to interpret the information you have received. And if you are too wrapped up in your own issues, you can still find it hard to be detached enough from them to clearly understand the information you are being told.

And, even after that, even if you accurately interpret the information, you still need to apply it in your own life...which is a lot easier said than done, whether you are a "vibrational reader" or not.

It's sort of a case of "Physician heal thyself" syndrome. Stingray has it pretty well covered. I would only add that the emotions get in the way when psychics try to read for themselves. It's often the same with healers. It's about emotional attachment to the answer or results. Even psychics want to hear the good news instead of the bad. Often when psychics try to get answers for their own lives, there's an emotional attachment to the answer that muddy's the psychic waters. When a psychic reads for someone else, it's much easier to be unattached to the answers. This calms the psychic waters so to speak so the messages are more clear. That is unless the psychic is new to the game and lacks confidence and trust in their ability. But that is also an emotional attachment... to not being wrong. If the psychic is in a mental state of hoping for a "good reading", they might be too focused on not failing and end up getting in their own way. The best state of mind to be in when reading or doing healing for anyone, including oneself is "neutrality. This is being unattached to being right or wrong. This is when the emotions are completely calm and there is quiet within. Then the psychic is unattached to the outcome and the answers are more accurate and helpful. Few know how to be neutral about their own issues in life.

This is an excellent question.

I'd agree with everything Stingray had to say, but I'd add another point as well.

Keep in mind that we are all human, and so we are all imperfect. It is extremely common for people to be unable to see their own flaws in anything, even when it comes to simple mundane topics.

This behavior is easily observable on a day to day basis if you associate with 'gossipers', because the vast majority of the time the things that an individual will complain about in an other is traits they share themselves. The funniest part about it is we very rarely are even self-aware enough to acknowledge we have any problems directly, much less the exact problems we are criticizing others for.

I'd say this is a very similar situation to finding a marriage councilor who is unable to handle their own marital issues, life coaches with life problems, shrinks with issues, etc. So while I agree there are definitely some supernatural explanations as to why this situation occurs, I'd say ultimately it comes down to the practitioner themselves, their belief systems, and their overall psyche / mindset. =)

The "psychic" power we have is Love.

Love does not apply to the self, only to those outside of self.

The work is important, the self is not.