There are three possibilities that spring to mind every time this happens. Firstly I think of the writings of Terry Pratchett and his characterisation of Death, who says that when people see things out of the corner of their eye they dismiss them as not being there as what they are seeing does not fit with their world view, but in reality they are there, that is why no one sees Death as they don’t believe in him. I am not saying that I am seeing Death lurking in the corners, but I keep seeing something/someone.

