When do you get mad?

Bedtime tonight was excrutiating. Abby forgot to read a book for reading, Nolan was so, so pokey, and Max was just a little overtired and, therefore, crabby. Dinner wasn't as bad, but the battles of "How much do I have to eat?" along with the kids getting up, teasing each other, and doing literally everything except eating their dinner gets old. After all was said and done, and Dave finally got everyone tucked in as I fed Ava, I just looked at her and asked Dave, "How old are they when you start to get mad at them?" When I look at Ava I just can't imagine being mad or even a little upset, though I know, soon enough, I will be. But for the life of me, I can't remember how old that is. Nine months? A year? 18 months? How old are they before they should "know better"? I'm not sure, but I know I'm glad Ava's not that age yet. Lord help us when she is!