Especially if you're going over 100 miles per hour.
Aerodynamics are one of the most important aspects of car design, but it is also something which is basically impossible to see. But the YouTube channel The Slow Mo Guys (not usually automotive related, even though it's clearly awesome when it is) have thought up a good way to demonstrate just how air and even rain passes over a convertible with the top down. Shot in 4k at 1000fps on what must be quite an expensive camera, the video shows an incredible amount of detail.
It doesn't offer up much of an explanation of what's going on, but it's a perfectly good demonstration for those of us who don't have physics degrees.