Why dark matter/energy?
Take for example a firecracker, a hand grenade, a star or anything in our universe that explodes. If you were to measure the rate of expansion over time there would be points where the expansion is accelerating, remaining constant or decelerating. At the point in time when the explosion is accelerating, would you call the force driving that acceleration dark energy/matter? No? So why do we invent dark energy/matter to explain the acceleration of our universes expansion?