In my younger days, I experienced a strange phenomenon. When shopping at the grocery store, I would get a strange feeling when I looked at the lettuces piled up in the produce section. Kind of an internal shiver. It was worse with the darker leaf varieties - romaine, red and green leaf - but still happened when I gazed at even the iceberg or butter heads.
I call it "Lettuce Feeling."
My research has yielded few clues to the cause of this strange malady, and I believe I've only ever met another sufferer once. I wonder if there is a proper moniker for this condition.