I have been That Mom—you know the one I’m talking about. That Mom whose kid is running wild and doesn’t have a clue what to do about it. Who didn’t remember to pack a toy or a snack and who is obviously running low on patience.

There have also been times when I have been That Other Mom. The mom who appears preternaturally calm no matter the crisis, who has an endless bag of tricks and solutions, and who makes it seem as if she has everything under control.

If there is one constant in parenting, it is that everything changes. As soon as you feel confidence, as soon as you feel secure in your and your child’s routine, that’s when you are guaranteed it will all change. Some new challenge will appear, or miraculously disappear, and in the blink of an eye, you will go from being That Mom, to That Other Mom, and back again. All of us have experienced this to some extent, and yet we still have a tendency to criticize others and ourselves during the low points and compare ourselves to others’ high points.

I think we, as women, tend to compare. These comparisons can be benign and conversational, such as, “Look at her handbag!” or “Who does your hair?” But often they can run deeper, to things like body image, lifestyle, and even parenting.  It’s so easy when things are going well with your children to see a struggling mom and think, “Oh, I could have handled that tantrum so much better than her.” And conversely, nothing can quite cut through to a mother’s deepest insecurities as having a child out of control in public. Seeing another mother handle a tricky situation with poise and grace can make us question ourselves; yet I don’t know any mother who, when things are going well for her, actually sets out to make other moms feel less competent. The doubts that arise from seeing a calm, confident mom are almost always our own.

But that doesn’t make them any less troubling.

Recently I was out to dinner with a single, childless friend of mine. Across the room from us was a mom struggling with her son. Every offer from mom was refused; every attempt to distract him was met with a shriek. My friend turned to me and said, “I never know what to do in these situations.”

“Well, you could buy her a cup of coffee,” I jokingly replied. The truth is, when we are That Mom (and we all are, at some point), what we really need is camaraderie. The sympathetic smile that says, “Yup, I’ve been there,” the offer to hold the shrieking baby so mom can gulp down food, or yes, even the odd free coffee.

Later that evening I was instant-messaging with a friend’s twelve-year-old. She was telling me about her new ballet class and how she felt scared about moving into an advanced class. I wrote back, trying to instill confidence:

“All those other girls have felt just as unsure and out of place, at some point, as you do now. Don’t ever compare yourself to anyone other than you. Go ahead and ask those girls for advice, but don’t forget that you are as good as they are; they just maybe have had more practice. And one day you’ll see a girl who is struggling a bit and remember to be kind and help her out too. You guys are all in this together!”

So often, the advice we give to our kids is exactly the advice we moms need to hear ourselves.