I just realized that I have a fear of downstairs toilets.
I have a memory of sitting on the toilet in my home as a child, my feet only just touching the U shaped toilet carpet, and suddenly seeing an insect - a beetle or louse or something. I screamed and ran out, paying no attention to the circumstances of the act of using the toilet. My mother and siblings could not find the insect, leaving me knowing that it was there, hiding, waiting for me to be alone again. In the 15 years that followed I used the toilet upstairs, unless circumstances dictated that I use the downstairs one. In these few instances I would rush, ensure my feet did not touch the carpet, and rapidly move my eyes around the floor, looking for this insect to show itself. It never did.
