First of all, I've been reading this forum for a while and picked up lots of great advice, thanks to everyone for those!
But to the point: I certainly know how to use ISO setting, aperture and shutter speeds for various situations, but what I don't know is why on earth all of this knowledge just flies straight out of my head when I'm shooting! My head seems to be completely empty as for using correct settings for the camera, especially when shooting something relatively fast paced (different events with action and people).
Many times I really wonder for myself why I have used aperture f10 when shooting people indoors, or why I have thougt that 1/100 sec exposure time was enough for running horses? Afterwards I realize I haven't even looked at the settings when taking the pictures! And when the shooting situation changes, the old settings are of course usually wrong. How can you really miss such a thing!?! Does this ever happen to you? And how can I practise to learn to prevent this in the future?