I was reminded just how contagious laughter can be last weekend while I was driving along listening to the radio. The show was funny, but the guffaws and giggles were just as good. I laughed right along, alone in my car.

This got me thinking about people and their laughing styles. I could line up all my relatives and label them by their laughs. There's the one with the explosive laugh that rattles windows. There's the one whose much quieter laughs make her stomach jiggle. Then there's the one who, when she really cracks up, stamps her foot up and down.

The latter is the girl who, at the hysterical age of 5, said, “Laughing is like having your feelings tickled.”

We all know people with distinctive laughs. We have a friend now living in Florida we rarely see anymore. But I know I would recognize his loud, uplifting laugh anywhere – even in a busy airport.

There are people whose laughs we may find annoying and others that are simply unique. High-pitched. Boisterous. Cackling. Chortling. Broken up by snorts. Or, as Mary Poppins pointed out, some people laugh through their noses, some people laugh through their teeth.

And let's not overlook the giggle-laugh, the silent laugh and the unstoppable laugh.

Years ago, I had a housemate who, while reading Dave Barry's column in the newspaper on a Sunday morning, would be laughing so hard in the other room I'd have to go check on her. This would make her laugh even more. Then I would start laughing. We acted like 12-year-olds.

This housemate is also a cousin, and early on I pegged her as having a laughing problem. We all know that a good laugh is good for us, but it also can land us in a heap of trouble. As kids, this cousin of mine would burst into uncontrollable laughter at the dinner table and attempt to remedy the situation by drinking her milk. This, of course, ended in a big mess.

I also learned not to sit near her at events at which we were supposed to use our “quiet voices.” A solemn church service, for example.

Years later, as young adults, I remember her laughing so hard in a quiet, darkened movie theater that she rocked our entire row of seats. She covered her face with her coat but still couldn't compose herself until after the movie had started.

I'm one to talk. Recently, after realizing I had placed my coffee order into the garbage can instead of the drive-thru speaker near it, I lost it. I could barely speak, in part because I knew I had made the same mistake before.

To a parent, kids' laughs are the best, of course – at any age. Whenever our daughter really gets on a roll, the dog comes galloping in to check out the performance. Nudging her with his wet nose only gets her laughing more.

And, yes, that is a big smile on his face.