Must admit, I am one of these leave-the-foil-in-the-margerine/butter-tub brain cases. I have done this for my entire life and have never once questioned the action, nor paid any attention to why I do it. Maybe I saw someone do this at a young age and it stuck (probably my maw, the weird cow).
It is now that I have seen the error of my ways, and will change this immediately. In fact, once I have finished this post, I will journey to the fridge and remove any currently existing foil. Even from the f**kers that I haven't opened yet.
Thank you, residents of Pie & Bovril.
Death to the foil-leaver mutants.