The shag carpet of the house we lived in when I was 18 months old.
It was green, and I remember that I thought it was funny and that I would run my fingers through it like it was fur.
I also remember the octagon window that was on the landing of the stairs. I remember looking at it while being carried up the stairs.
I can barely remember what I ate on Monday, lol, but I remember all the houses (we moved a lot) of my childhood, starting with that one, very vividly.