Yes, I am also inclined to believe this is just natural human psyche phenomenon.

This very specific topic about clovers is one that I relate to, I've always found 4 leaf clovers faster. But I wouldnt say I have synesthesia.

This has developed/manifested itself into looking for things on a computer screen, which I essentially do for a living. I can hold a piece of text in my head and scroll by quickly to search for it much faster than many of my peers.

And as a child colors would also have numbers related to them in my mind, and vice versa. Which I attributed to number-coded coloring books.