So I was putting this half-eaten pasta into the freezer and it slid in nicely on an empty shelf, but the person to whom it belonged wanted it covered in cling film, so I wrapped it right round twice with cling film and again slid it into the fridge, but this time it did not slide. Something was blocking it. I was sure the shelf was empty but obviously something was in the way. Then I realised the cling film was not sliding, but sticking to the shelf. It took me a while to realise this.
I intend to write a follow-on post to this one called 'Fridge 2: Twice Clingy".