Interesting question. I never thought I'd say this...but I think there may be such a thing as hair that's too long.
I adore stick straight, center parted hair. Dark silky Asian hair,or Blonde hair with dark roots REALLY push my buttons.
For my tastes, waistlength is wonderful , knee or thigh length is HEAVEN!
Any longer then that , it does lose some impact for me. And the ends don't seem to be that healthy & full.