Do you associate certain names with a particular hair colour? I just added a comment to the Nina thread and realised for me it is a red-haired name. In this case it's because the only Nina I've known IRL was a red-head, but whenever I hear a name I invariably picture the hair colour I associate with it, based on no logic whatsoever even if I don't know anyone with that name or where I know several people with the same name but of different colouring.
E.g: blond(e) names = Sarah, Olivia, Amelia, Felicity, Karen, Alistair, Charlie, David, Rupert
Brown-haired names = Fiona, Megan, Francesca, Rosalind, Mary, Alexander, Hugo, Paul, Robert
Red-haired names = Nina, Molly, Katarina/Katy (but Catherine/Kitty is blonde), Helen(a) (but Nell is blonde), Sam, Joshua, Jake