Try these two great on-screen Rider Perception tests from the Motorcycle Safety Foundation. Then try them again, the obstacles and signs change, and you can adjust the speed.
When you’ve been riding a lot, and you’ve been trained to see obstacles, they start to jump out at you. Critics of MSF (and thankfully, there are few) argue that training does not reduce risk when riding. I agree that it’s important to remember that you’re always at risk, regardless of training. But even simple bits of knowledge like “metal plates and manholes are slippery” give riders an edge, how can anyone argue that it’s not worth learning as much as possible about hazards and two-wheel physics?