True story (I swear).
Over the holidays, I was in the ladies stall tending to business and a child goes into another stall and starts singing some operish, religious song at the top of her lungs (best way I can describe it). I semi-annnoyingly tell her to give it a rest.
She stops for about 2 seconds and then keeps going. Now I'm washing my hands and she's still in the stall singing at the top of her lungs, so I lose it and yell, "SHUT THE FUCK UP!"
I was having a bad day, but damn, shut the fuck up!
And this is coming from someone who loves kids.