Why do people on bicycles and scooters feel that they don't need to follow the laws of the road?

I see it all the time. Just today my husband and I were running an errand. Just as the front of the car began to enter an intersection, where we had the right of way because the cross street had a stop sign, some guy, an adult, on a bike came flying up to the intersection. He quickly checked both directions OVER the top of our car and he never even saw us. He flat ran that stop sign and he didn’t slow down or hesitate one bit. In fact, when he thought it was clear he stood up on his pedals and accelerated. I fully expected him to slam in to our rear fender, but somehow he missed us. Couldn’t have been by more than 6 inches or less.

Another time I saw a gal on one of those motorized scooters that you stand on, like a push scooter. She came up to a 3 way stop. The corner that didn’t have a stop sign was the entrance from the street to the Walmart. She never even slowed down for her stop sign. She flat ran it. It turns out that she worked at the McDonald’s which is where I was heading anyway. I saw her there and commented on the fact that she had run that stop sign and could have been hit. She looked at me like I was crazy.

What are these people thinking?