Raising a polite child has been a priority in our house. Please, thank you, and excuse me are prompted and modeled. We've had great results.
I was never more aware of this than on the playground last fall. I stood in a circle with two other moms, chatting as our daughters of roughly the same age played. We were laughing at their conversation as they learned each other's names and became fast friends.
Then my girl who is a good 20 feet off very loudly says, "Excuse me, I farted." We all chuckled. "Kids are so honest," one of the other moms observed.
Julia is either too polite or too honest. She must excuse herself for farting twenty times a day. Most times, no one even hears said fart. I once tried to explain to her that silently breaking wind doesn't need an announcement. She didn't get it.
Society will most likely embarrass this behavior out of her (the apology, not the gassiness), but in the meantime she calls herself out every time. Refreshingly honest. Pleasingly polite. Tragically flatulent.