It’s also a helpful trick to use at the end of your flight when you need more space to stand up and grab your luggage from the overhead bin. Instead of doing that awkward, half-backbend lean to grab your bag from above you, while also trying to avoid touching your neighbor, just put up the armrest and easily get out of your seat.

But, that’s not all this button was intended for. While it does provide some much-needed relief from the constricting boundaries of an airplane seat, its sole function isn’t to give you more room. It’s actually a safety measure to allow a quick and easy escape should you need to make an emergency exit from the plane.

So, on your next trip, make the move and choose the aisle seat. Go ahead and push that tiny button. Your sides will thank you, and you’ll probably blow the mind of your fellow passengers.