Apparently none you guys read past the first clause of what I wrote. Did I say that I use full auto on my camera? No. Did I say you should? No. Here, I'll try again, with emphasis to make it easier:
So in other words: You encountered a good reason to believe that in your situations, the camera would probably guess certain things incorrectly, and so you started using those particular settings manually again.
Which means you did precisely what I just suggested people should do.
I'm glad we agree.
When shooting most advanced users have a precise idea of what they are looking to get from the shot and adjust accordingly. The camera guesses what you want based on programming.
Yes, but not every variable is RELEVANT to the precise vision of the shot you have in your head, in some situations.
What does a sports photographer care whether the shot was at 1/1000th of a second or 1/2000th of a second, as long as there is no motion blur?
What does he care if it's ISO 100 or 400, if he is using a modern full frame camera, and neither is going to show visible noise at his final print size?
He doesn't care, and thus it would be a waste of time for him to manually shuffle between 1/1000th or 1/2000th or ISO 100, 200, 400. The auto math system would do better, as long as it is constrained within the range of values that don't matter for this particular shooting situation.
Similarly, if auto focus is precise enough to focus on what you intended it to focus on, then it would be a waste of time to use manual focus ANYWAY, because it wouldn't do anything to help you better accomplish your vision for the shot.
In fact, spending your time doing either of these things, if they are unnecessary, would actively hurt your photography, because you would be more likely to miss shots while fumbling.
You're right that the camer guesses based on generic programming. But whenever generic programming is expected to match your own decisions (which is predictable as to when it will), then the programming is better, because it's faster than you.