1. Bodily fluids aren't just in the bathroom.
Wiping up a bathroom is disgusting enough, but trying to both clean up poop and save the carpet you got as a wedding gift from your MIL, least she thinks you ruined it on purpose, is a certain brand of torture.
2. No matter how often you vacuum, the carpet will always be crunchy.
Try as you might to keep the eating in the kitchen, crumbs still manage to make their way all over the house. Whoever thought up the concept of an open floor plan most definitely did not have toddlers.
3. You no longer know exactly what color your walls are.
Are they beige? Cream? Hard to tell anymore, but that smear of strawberry jam in the dining room is making you think that's a perfect shade for an accent wall.
4. "Clean" clothes is a relative term.
Clothes that are clean enough to wear in public and clothes that are clean enough to wear around the house are two completely different things once you're a parent. And if your child is sick, be it in public or at home, that shirt you are wearing is now a walking Kleenex.
5. You know you mopped today, even if the floor doesn't look like it.
No matter how well you mop, as soon as the next meal is over it will look like the floor hasn't been cleaned in a month. I try to time my mopping for right after a meal to maximize the clean floor for as long as possible and protect my sanity.
6. A hand print covered window is as clean as it gets.
You can have the patience of the Karate Kid and still never get your windows perfectly clean with kids around. A clear pane of glass is like a blank easel to a child- they simply must leave their mark. As long as there are no discernible drool marks, call it a win and move on.
7. Letting your kids "help" you clean really makes more work for you.
Getting the minions to do your bidding isn't as easy as you thought. Yes, the laundry will have to all be refolded and you'll need to re-wipe every surface they touch, but at least they won't go off to college unable to do anything for themselves.
8. A room is still clean if there are toys on the floor.
Ignore those glossy catalogs that tell you toys should be organized into color-coordinated bins according to type. As long there aren't tumbleweeds of dust blowing through the Barbies, you're doing alright.