My Eureka moment
 

I went for a ride this morning and after about a mile realised I had my everyday glasses on, so stopped and put my wraparound cycling glasses on from my rucksack.

When I started riding again it hit me for the first time that the wind noise I get when riding is due to the cycling glasses directing the airflow direct to my ears. It doesn't appear anywhere near as noisy with normal glasses.

How dumb, why has it taken me all these years to find this out?

NOT dumb; you're used to swapping specs, and you EXPECT wind noise when you ride -- why would this even be a THOUGHT? All you did was make a DISCOVERY. Now it's up to you to figure out what you're going to do with it.