Virtually all of us "lose it" with our kids at some point. Then later we say, "I didn't want to yell at my child, but I couldn't stop myself."
If you want to avoid these parent-child "collisions," you have to pay more attention to your "inner stoplight": stress.
Suppose you're worried about getting your child to an appointment on time. Worrying is stressful, so it's a red light telling you to stop and get centered before moving on. But long ago you were trained to tolerate stress, so you don't notice the red light. You're on a collision course!
Which parent is more likely to end up yelling, the one who's centered or the one who's stressed?
Today, pay close attention to your subtle feelings. Decide that even "mild" tension or irritation is a red light. Stop, breathe, reach for better-feeling thoughts, and wait for the green-light feeling of relief before you take action.