I noticed this dynamic in action this afternoon when riding a brand-new local beginners trail, this was the first time I've ridden it and it is so new that few people know it is there just yet.

This trail has no exposure at all, it is pretty much totally flat. It does wind a fair amount between trees and found myself grabbing a tree or two because I was looking at the tree and not at the way through the trees. I know better... I just kept repeating two things to myself - "pedal, pedal, pedal" and "look down the trail, don't steer"

Then I got in some mud accidentally, no traction, fell over with my bike, and actually hit the TOP of my head/helmet on the ground It was a soft yet firm hit, we will see if I've a stiff neck in the morning. It was just tacky mud and leaves, so nothing hard or edgy struck my lovely Fox Flux helmet. Thankfully there was a hole in the ground next to a log where the end of my Ergon grip bar-end fit perfectly, so no damage

The odds of falling and ONLY hitting the TOP of my head on the ground again is pretty slim to none I think

I appreciate the advice and will follow up on it. I suspect that a lot will be solved by allowing myself to go a bit faster and looking further down the trail - and I am getting better at the latter.