Something tripped me up (and it wasn't the cardboard box)

I am a gobshite.

I've just spent the past ten minutes arguing with my 8 year old about how far she can leave her door open at night.

Too much and then too much light is let in meaning she doesn't get to sleep. Too little and she complains of being scared of the dark (a cunning ploy to make sure she can listen in to us I'm sure).

Me: you can't leave a cardboard box wedging the door open like that. Ridiculous. That's why I bought you a doorstop for Gods sake!

Her: you didn't buy me a doorstop, Santa did.

Me: .....

Damn it, this Christmas lark is a tricky business. Any advice oh wise ones?