I find something similar happens when mowing the lawn. When I try to mow in straight lines by pushing next to the previous row, I end up with wavy shapes. But when I fixate on a distant reference point beyond the lawn (like a rock or weed sticking up above the grass) and just walk staring at it, I end up with perfectly straight lines. It's uncanny.

This is also a trick for drawing surprisingly straight lines on paper. If you start at a point and watch where you're drawing, you'll end up with a terrible line. If, however, you start at a point, focus on your target, and move the pencil towards the target, the result is surprisingly good. Also works for circles.

It's especially a problem with motorcycles because many of your natural fear based reactions are exactly wrong for the situation.

Example: you come into a corner a little fast, see you are going a bit wide, fixate on the ditch/edge of road, get afraid and hit the brakes - which stands the bike up and drives you wide; sometimes right off the road.

The right response here is to look away from the ditch to the line you want on the other side of the lane and lean into it more. Easier said than done if you are afraid or anxious.