Bless me for I have sneezed

I told Pants I was bored, so he told me to post. I'm talking to myself here anyways, so what the heck, I'll talk about sneezing.

Why does everyone feel the need to acknowledge a sneeze? A co-worker sneezed about five minutes ago and I almost told her "Bless you," but stopped myself. A guy next to her had already said "gazoontite," so I felt she was covered.

It's almost like some kind of insurance policy, but with guilt involved. If you don't say something, will the person that did it be embarrassed or upset that you didn't acknowledge it? Or if you do, will they be offended at you using a religious reference?

I've read that "Bless you" started in the Dark Ages, when it was thought that a sneeze was evil spirits leaving your head through your nose (or entering it, I can't remember). If someone "blessed" you after/while you sneezed, you were somehow, despite the lack of religious qualifications of the person doing the blessing, safe from said evil spirits.

I often say "Bless you" as an automatic response, but, when I can help it, I like to withhold and see how people respond.

I know when I sneeze, I'm hoping it's the evil spirits of allergies leaving me, but they never seem to really go away, despite numerous blessings from others.