Oh, oh, it's Henry, you knoooow! Never believe it's not soooooo!
Ahem, sorry. Anyway, here's a little ditty that pretty much everyone is required to read in high school, usually to teach the apathetic children what irony is. The lesson is rarely learned, of course, but that's hardly the English teacher's fault. Or O. Henry's fault, for that matter.
In any event, as our story dawns, Della McWife is getting all emo about Christmas. She lets her hair down while deep in contemplation and the narrator helpfully notes that the locks fall well below her knees. I've gotta tell ya, that sounds like hell to manage. She must go through shampoo like water.