I agree. Little quotes/sayings can be fun, but the car is not the place to put them, as there's no way to discuss it with the owner. This is why all the sticker's I've ever had (other than those sitting around without purpose) are somewhere like in the office, or on the computer. This is also why I like taking pictures of some of them and posting them here - right above an "Add Comment" link...
Since we're on the topic of bumper stickers... Relevant just had an article this week talking about Christian ones. The article is short but still has some good points.
One can only hope some of the people with their cars covered with them will actually read that.
Copyright ©2000-2008 Jeremy Mooney (jeremy-at-qux-dot-net)
I remember a comedic sketch I heard once, it went something like this:
"I appreciate people that put bumperstickers on their cars. It's there little way of saying 'don't even both talking to me because I suck. I'm the kind of person that thinks the only way to make a statement is to plaster my car with hokey sayings. Have a nice, bumpersticker free life"
I stand by that sketch :)