Rationality witticisms suitable for t-shirts or bumper stickers

What are your best short wit­ti­cisms, suit­able for use on a t-shirt, bumper sticker, or similar lo­ca­tion? Ideally some­thing that might make some­one read­ing it think, or get cu­ri­ous enough to ask about it. Sim­ple in-group iden­ti­fi­ca­tion is fine too, though.

For con­text, therufs is spend­ing to­day at the NC Maker Faire mak­ing t-shirts, and asked me for sug­ges­tions this morn­ing. As I was still mostly asleep, I wasn’t very helpful.