Long-haul flights are the worst, aren't they? You spend the whole time trying to get to sleep, and when you finally start to drift off, the flight attendant asks you to open the window shade. Ugh.

Dazzling light floods in and, yeah, it means you're about to land, but why do they do it? Is it just a cruel trick to punish you for turning your nose up at the microwaved mushfood?

Well, no, not exactly. Tech Insider asked one flight attendant to explain, and they revealed that, actually, they ask you to raise the shade for your own safety, thank you very much.

MORE: 10 THINGS YOUR FLIGHT ATTENDANT WON’T TELL YOU

The stewardess said:

'If there's an emergency, we have to be able to look out of the window to assess outside conditions. If there is debris, fire, or water blocking the window, we won't use that exit and will direct people elsewhere. It may seem like a small thing, but in an emergency, every second counts. You don't want to have to fiddle with a window shade when you're trying to evacuate a plane safely in 90 seconds.'

Now it all makes sense, doesn't it? So next time a flight attendant asks you to open the window shade, do so with the best smile you can manage, safe in the knowledge that they're looking out for you.

From: Cosmopolitan UK