Not a bumper sticker at all, but I saw some campervan aound whose owner really seems to hate dogs.

Every window was plastered with semi-rational writing on why dogs should all die.

Trump 2020

I don't pay much attention to them IRL but Daniel reminded me of one I saw on Reddit (I think) that was anti-Greta but they also had a pair of braids hanging out from the trunk like she was in there, like people do for a Halloween decoration or something

"Fuck You Greta"

"Hot rods do it better" ... there is no real bumper sticker culture here in belgium.

Some dude had "CNN is FAKE NEWS!" plastered on his rear window between an InfoWars logo and a picture of Obama in Muslim garb. I don't think he was trying to be ironic either.

"thank your mom for being pro life" as if every pregnancy is an accident. What a got damn idiot. Also there's a car I see occasionally with a license plate that says "sexy mom" but her windows are tinted so I havent been able to confirm if it's true or not

Not much of a thing where I am, but I do remember 'stop staring at my ass and keep your eyes on the road'