What keeps you from feeling every single pebble in the road, like the Princess and the Pea? Mainly, your car or truck's suspension system: The springs, shocks and struts.
Every car and truck has springs. When the vehicle rolls over a bump, the springs compress. Once over the bump, the springs expand. In this way, the wheel rides up over the bump while the vehicle stays level.
Of course, the spring then wants to expand and compress over and over until it gets rid of the energy from the first compression. But that would make the car bounce like a Bobblehead down the road. So to control bounce, cars and trucks have shock absorbers and struts. Shocks and struts keep the tires on the road, giving you control for steering and braking. That's how they provide safety and driving performance, as well as comfort.
To some degree, the desire for a soft ride is in conflict with the need for accurate steering. So shocks and struts find a balance between the two.
If your ride has become rough or bouncy, there are several things to check. Shocks and struts do wear out. If it's been 50,000 miles or so, it may be time for a shock or strut replacement. The air pressure in your tires matter, too. Tires with too much air are bouncy—and not very safe, because they don't have enough footprint on the road.