I've figured it out. Cutting your hair is cutting yourself free from the accumulated past. All that hair was around when things from your past you might not want to remember happened. By cutting your hair short, you're removing all but the most recent growth, the most recent past. So those women who cut their hair right after they get divorced are removing themselves from their past -- their marriage -- so they can start fresh. (As for Samson, I think that had to do with a pact with God or something. But maybe Delilah was cutting him off from his heritage -- his past -- as well as his strength when she cut his hair. Or else I'm just making shit up again.)

Except I'm not trying to get free of my past. At least I don't think I am. Though moving back to Victoria to finish my writing degree was liking coming full circle, right back to where I'd left things when I moved away to study archaeology. So now I've moved to Duncan and cut my hair to escape the circle and start someplce new. Except that's not it at all. Not really. I'd already started off in a new direction (more or less) before I cut my hair. So I still don't have the answer. Oh well. I rather like it short.