I was thinking, what if body's resistance is actually the norm, even when there is no change of velocity ? But the negative mass would provide the energy to let

I was thinking, what if body's resistance is actually the norm, even when there is no change of velocity ? But the negative mass would provide the energy to let the body's in movement ? From our point of view it seems that body's can move by theirselves and it seems also that we have to provide energy to change their velocities. But if we think the universe as a fluid, body's should be constantly slowed. It's very strange to have two distinct behavior, except if we have a negative mass in the universe.