Patience. So that when your child says "mommy" forty times in a row, you answer "yes, baby" in your sweetest voice each time. And so that you don't lose your cool when you explain for the umpteenth time that the cup should be placed nicely on the table when he's done drinking and not thrown on the floor so that the leftover milk spills all over the place.
Flexibility. Because sometimes when you make plans, your kid has made other ones. And sometimes, a clean house is just not that important.
Forethought. Because you never know if (or when) your child is going to get hungry/thirsty/bored, and so you must always have snack/water/games.
A backbone. Because "no" needs to mean "no," even if it causes a tantrum. And bedtime is bedtime. And you have to sit in a car seat when in a car. And there is only one dinner and if you don't like it, you don't have to eat it, but you're not getting another dinner (or dessert).
Sense of Humor. Because sometimes you will get pooped on (both literally and figuratively). And you just need to have a laugh...