The Problem With Quantum Gravity

Gravity is complicated because everything is affected by it. It's not like electromagnetism where you can like shoot out photons and those photons themselves don't feel electromagnetists. Gravity interacts with everything with energy. So anytime people build a theory of quantum gravity, it just sort of predicts nonsense. We just can't mathematically make it work. And then there's the experimental challenge - trying to build a setup where you can see the gravitational effects on particles.