My wife bought a phone (for the house). I watched her frantically searching through the box it came in.
When I asked her what it was she was looking for, she replied "the phone number" (she has a degree in English, I know incredible isnt it).
I told her she would have to take it back to the shop and exchange it...
...and she did!!!
And I let her do it.
I've never allowed her to live it down.