A few days ago I was in a park, and somebody came to me and very politely recommended me to take off my sunglasses. I got immediately prepared for an argument, because it is a strange recommendation, and I thought I did nothing wrong. Why would anyone think wearing sunglasses is inappropriate?! But then the person explained that during that time of the day (around 10am) it’s beneficial for my circadian rhythm if my eyes are exposed to the blue light.
It turns out somebody even got a Nobel Prize for this discovery.
Thank you, stranger! Though I will still wear my glasses when cycling for safety reasons.