The instinct of self-deception in human beings makes them try to banish from their minds dangers of which at the bottom they are perfectly aware by declaring them nonexistent, and a warning such as mine against cheap optimism was bound to prove particularly unwelcome at a moment when a sumptuously laid supper was awaiting for us in the next room.

Simply minding one's own business is more offensive than being intrusive. Without ever saying a word one can make a person feel less-than.

Sometimes things happen that give me cause to believe I no longer exist. Car park barriers which do not lift when I drive towards them, automatic doors which do not open automatically as I approach.