Bumper stickers can be an eyesore, a way to induce road rage and a way to make us LOL while we're driving, but they rarely say anything we should take seriously.
Because only a total crackpot would think a bumper sticker stating their cracked opinion about an issue would have the power to actually change someone's mind.
Of course, there are plenty of witty and insightful bumper stickers out there, with slogans we can actually get behind, so we can't entirely dismiss the power of their slogans to stick in our minds.
But who wants to read some racist, sexist or religious slogan some crackpot felt like sharing with the world when we can read silly slogans we'll actually want to share with our friends?
And why would you want to use your bumper sticker to shove an agenda down another driver's intake manifold when you can make people smile with a silly slogan?