Sunday, May 12 is Mother’s Day in the United States and Canada.

Some people think it’s ridiculous to celebrate holidays like Mother’s Day and Father’s Day – that these are just commercial holidays forced on us by clever marketers. But I think it’s nice to be prompted to think lovingly about your mother and your father, and the mothers and fathers in your life.

I often contemplate an observation made by my spiritual master, St. Therese of Lisieux, in her extraordinary memoir, The Story of a Soul.

While writing about being blamed for things and scolded for little transgressions in her convent, she noted, “I noticed this: when one performs her duty, never excusing herself, no one knows it; on the contrary, imperfections appear immediately.”

So true, right? You do something perfectly and reliably, nobody notices. You make a mistake, everyone complains.

This is particularly true of parenthood, which involves a myriad of tasks, small but pesky and relentless, that need to be done without fail. “I packed lunch for four years,” a friend told me, “and all I hear about – to this day – is that time in first grade when I forgot to put in my son’s dessert.”

It’s true that parents don’t get a gold star for everything they do right, but often, just hear about it when they mess up. But it’s also true that, as my mother once told me, “The things that go wrong often make the best memories.” Here’s an example.

Of the countless times in my childhood when my mother drove carpool, or picked me up to go to an orthodontist’s appointment, or wherever, I have only the haziest recollections. All I remember is the time when she was very late picking me up. But this is an important memory.

It was a very snowy day when I was in grade school — fourth grade, I think — and my mother was late. She’s completely reliable, so I was anxious about the fact that she wasn’t there, and I was embarrassed about being left over when all the other kids had gone home, and I was worried about what would happen if she didn’t show up. She didn’t come, and she didn’t come, and finally I was sent to wait in the library, in the main building of the school, until someone came to get me.

It got later and later. I could feel the building emptying out. Still no sign of my mother. The snow was getting heavier. I was getting more and more anxious.

Finally, I saw my mother coming up the steps to the library, and I had to fight back the urge to burst into tears from sheer relief. I was so happy to see her! She was staggering under the weight of my sister, who was probably four or five years old, both of them covered with snow, and she was slipping around on the unshoveled walkway as she battled her way to the door.

And I thought to myself, “Nothing can ever stop my mother from coming for me.”

I remember that her car had become stuck on a patch of ice, but I have no recollection of what happened next. Did my father come to get us, did the school receptionist give us a ride? I’ve never asked my mother about that afternoon, so perhaps my memory isn’t even accurate. But that’s how I remember it.

And that’s how I think about my mother.

Gretchen Rubin is the author of the #1 New York Times Bestseller The Happiness Project—an account of the year she spent test-driving the wisdom of the ages, current scientific studies, and lessons from popular culture about how to be happier—and the recently released Happier at Home and Better Than Before. On her popular blog, The Happiness Project, she reports on her daily adventures in the pursuit of happiness. For more doses of happiness and other happenings, follow Gretchen on Facebook and Twitter.

Image courtesy of Jordan Rowland.