My two year old's aunt took away his juice box because he was squirting it all over the car and he was pissed. He yelled at her and shook his finger at her. Finally he just held his breath for a second and then yelled, clear as ever, "SH*T!!!!"
And then when we couldn't stop laughing he just said it over and over and over, which wasn't great, either.
I'm not sure who taught him that particular word. Even though I do swear (a little too much) that doesn't happen to be one of my words. Unless I don't know myself as well as I thought. Hmm . . .