I, having just read an article like this, said "That's ok, sometimes saying a bad word can help you process your emotions and feel less stressed. Do you want to go down to the basement where nobody can hear you, and say the bad word?"
"Yes". She goes down the stairs, I close the door, and she yells at the top of her lungs: "I can't fucking find it!". I managed not to laugh, she comes back up, "Do you feel better?" "Yes." Great moments in parenting. :-) (We did eventually find whatever it was.)