We see faces and figures where they don't exist.
Pareidolia (derived from the Greek eidolon (εἴδωλον): 'figure' or 'image' and the prefix for (παρά), meaning 'next to') is a psychological phenomenon in which a vague stimulus is erroneously perceived as a recognisable form: we perceive familiar faces or figures in unexpected places.
Our brain is able to recognize patterns. Our visual system is sensitive to stimuli. It is part of the brain's ability to cope with a large number of stimuli. It is something unconscious and that allows us to make recognitions.
This anecdote comes from the photos that illustrate these lines. Today, as I was cooking as a family, I saw hearts on the onion. That reminded me of an old photo of a mug in which there was a little soda and I also saw a small heart that was drawn on the bottom thanks to the remaining liquid.
Some will say that this is completely normal and the most romantic would venture to say that "you see love everywhere when you really feel it". The truth is that by researching this I was able to name that phenomenon that makes us see faces in vehicles...or hearts in onions and cups.