The ball doesn't bounce back as high as it fell because it cannot store all the energy it had when it hit the ground. Some of that energy is lost to heat. That's why a basketball warms up when you dribble it.
Bounciness depends upon what a ball is made of and how it's put together. In a “Bounciness Olympics,” superballs would take the gold. Made from a special hard rubber, superballs return to their original shape when dented without losing too much energy.
Most hard surfaces store and release energy better than soft ones. That's why beanbags don't bounce very well and why rubber balls bounce higher on cement than on carpet. Now, when you're told the living room is a bad place to play ball, you'll know why.