I remember going to then my local Richer Sounds in Stockport to buy a Yamaha cassette deck I lived in Newcastle Staffordshire! Paid the money jumped on my motorbike and drove back. Unpacked the thing and noticed all the front was marked,so back on my bike and off I went.
Explained it to the salesman, who replied! You haven't removed the protective plastic film that protects it from scratches!
He gave me a Richer Sounds mug and a lollipop and off I toddled.
I felt like a right p...k.
I remember pointing out a loose connector under the bonnet of my car. "I think that might be a problem", I said to the old service bloke.
He just slowly turned and pointed to this diagnostic machine. "We plug that lead into the machine over there", he said.
It is hard to make an exit in fool mode !