We've learned over the years that parenthood is in large part having some new thing you never worried about before come around a blind corner and bite you in the face.
Sometimes it's literal. Kids get teeth eventually and you feel like an idiot for not thinking through the consequences of the "trick your kid into biting the end of your nose when they were trying to give you a kiss" game.
Sometimes it's more figurative. Like when your child learns to crawl and you forget you can't just plop them down somewhere and walk off only to find them a few minutes later banging glass baby food jars on the tile floor. (If you've never tried this, it does make a cool, unique, dink dink sound and after your child ventures into the pantry one or two times you will recognize it instantly.)
Sometimes you really should have seen it coming. Like when your four year old decides that as far as he is concerned, dinosaurs STILL rule the earth. And when he gets a toy tyrannosaurus figurine for his birthday he carts it around everywhere for over a month. And reminds you that T Rex needs to watch TV (when you have decided your son can't), needs to go to bed or take naps, and really really likes melted cheese on top of his hot dog. You'd think you would expect Rex to be around but occasionally he'll just show up somewhere and take you by surprise (you see, figuratively biting you in the face). Like this.
But then sometimes you really just had no reason to predict what would come your way next. You've read the parenting books. You spend time with your kids. In retrospect it seems obvious but you just weren't prepared for...
Xenosaurus Rex - Space Faring Meat Eating Parent Rule Evading Dinosaur Who Takes Off His Helmet When He Is On Mars (and really likes melted cheese)
See, didn't see that coming, did you?