Even if you see a purple monkey flying past your windshield with flames shooting out of its butt as you're driving down the freeway, don't point it out to your kids. They won't see it!
Its kind of like how you're not supposed to try to teach a pig to sing, because it wastes your time and annoys the pig. Yeah, just never try to point out interesting things that are happening outside your van windows as you're driving down the road. Complete and utter chaos will ensue, followed by tears, cries, and general hysteria. Much better to watch the purple monkey, marvel at the pretty flames, and let your kids continue poking each other in the back seat.