I remember being called as Mia Maid president and being told to "pray about who would make a good first and second counselor and secretary". I did and got nothing, which was very demoralizing. So then I just picked my friends. I can only imagine what it would be like to be called to a position where you genuinely expect to be receiving guidance from God and then come up empty.
I felt that way about everything I ever prayed about.
What do you suppose is going on in the minds of the GAs? Do you think they really believe?
I was 2nd counselor to two different bishops. One was a closet NOM and pretty much realized that decisions were based mostly on human reason, not revelation. My BIL was bishop in the neighboring stake and was shocked that we didn't pray individually over each calling. We had a pretty transient ward and would often discuss 10+ callings per bishopric meeting. So, did we say 10 prayers plus the opening and closing prayer? No. But my BIL said we should have been.
The second bishop that I was counselor to really thought that every decision was direct revelation from god.
I think that the difference is mostly due to a difference in how people think. There's a huge difference in how we process information. There's also a huge difference in confidence in one's decisions. I'm always second-guessing every decision I make. (Chalk that up to low self-esteem or whatever.) Even things like, "Maybe I should have gone to XYZ for gas because it might have been cheaper there."
But, I know people who are uber-confident in every decision that they make. I'm pretty sure that some of them feel guided by god in the decision of what they had for lunch.
The brain is a funny thing. The more neuroscience I read, the more I'm convinced of it.