Ha, I can imagine the look on your face as you hit that unexpected patch of gravel - priceless! But in all seriousness, handling gravel obstacles on paved roads is a whole different ball game than on gravel or dirt roads.
For starters, if you're on a road bike, you're going to want to have slick, narrow tires to minimize rolling resistance and maximize speed. But when you hit that gravel, it's like trying to ride on marbles! Your best bet is to stay calm, feather the brakes (but not too hard, or you'll lose control), and try to keep the bike steady as you navigate through the gravel.
Now, if you're on a gravel or dirt road, you've got a bit more leeway. Wider, knobbier tires will give you more grip and traction, and you can afford to be a little more aggressive with your steering. But don't get too cocky - even the most experienced cyclists can come a cropper on loose terrain.
And as for bike design, well, if you're really worried about gravel obstacles, you might want to consider a cyclocross or gravel bike. They've got wider tire clearance, more upright geometry, and lower gearing, which can all come in handy when the road gets rough.
But at the end of the day, there's no substitute for experience and familiarity with the terrain. So get out there, hit the gravel, and learn to love the chaos! Just don't forget to wear a helmet, or you'll end up with more than just a few rocks in your spokes.