Playgrounds look like such innocent places. Coated in primary colors and plopped atop shock-absorbent tanbark, park equipment has no sharp edges, no pokey corners. What could be more liberating?

But anyone who’s logged pre-nap hours there will tell you the freedom is pure illusion.

Like life, playgrounds are governed by rigid, unwritten rules that can puzzle and plague you until you learn how to work within them.

Or around them.

Upon entering a playground, for example, you’re expected to smile at other mothers even if they don’t look like people you could possibly be friends with. Though you never officially signed up, you are now part of a club: the Desperate to Get My Toddler Out of My House Club. By not acknowledging other members of said club with a “Hi, how’d we get here?” sort of nod, you appear to be “too cool” for the club, which is not OK. The other moms will say rude things about your rump when you’re bending over to retrieve a sippy cup from the sand, and who wants that, really?

While friendliness among females is encouraged, speaking to other womens’ husbands — even just to say “Has your kid rented that swing for the day or can we get a turn?” — is strictly verboten and will only inspire more butt mockery. Don’t grin at other daddies, especially the ones wearing “I Heart Hot Moms” T-shirts. And under no circumstances should you offer to be the “teeter” to a hunky dad’s “totter,” no matter how pathetic and lonely he looks sitting on the thing by himself.

If, in an effort to instill your child with respect for social rules and public safety, you insist that he slide down the slide rather that climb up it, you’ll be labeled a micro-managing spirit-quasher.

If, in an attempt to encourage his creativity and curiosity, you allow him to climb up the slide, be prepared for your new reputation as a reckless scofflaw. (Also, have an ice pack handy for when his creative and curious teeth meet with the fast-moving feet of a child who comes bounding down the slide, the way God intended. And yes, you can tell which side of this argument I come down upon.)

Playground protocol is complex, as evidenced by the rarely verbalized but strictly observed Sharing Treaty: A parent is never (ever!) to offer another child a snack of any kind. Not a pretzel, a Goldfish cracker or a single red grape. There are allergy issues. Ingredient anxieties. And the ugly implication that the child isn’t being properly fed by her own mother.

Likewise will that mother blush and apologize if her daughter asks another mom to hand over a single Cheerio, even if she does it politely.

Whereas snacks are considered oddly personal, though, toys are treated as communal property the second they hit the sandbox. When another kid outrageously rips a truck, trike, ball or bat from your child’s hands, you must demand that your child “share,” which, in park lingo, means, “Let it go. We’ll snatch it back later when he’s not looking.”

Real life is not like this, of course. As grown-ups, we are not required to share our cars with strangers who admire them in the parking lot. We are not obliged to pluck out our iPod ear buds and hand them over to weirdos at the gym who say “gimme.”

But the playground is different. On the planet of parenthood, it’s like its own sovereign nation with strange and stringent customs that feel as foreign to us as … well, as trying to scurry up a slippery slide. Don’t be fooled by the cushy padding underfoot. Bungle your jungle gym etiquette, mama, and you’ll land with a painful thud.