I enjoy watching fat people get into vehicles to see how low it dips.
You seem to enjoy observing things.
It is a passion of mine.
While it seems like you aren't hurting people by watching them get in and out of their vehicles, many people are so self conscious about their weight that they will notice you staring. It can really hurt someone, permanently, to see someone laughing at them because of their weight.
They are the idiots who put themselves in the situation. You made yourself fat, so you deserve to feel uncomfortable in your own skin.
Even if they did it on their own you should not make fun of them. What if you get fat one day would you like people making jokes about you in secret?