Reading through this, what struck me was the disconnect between my behavior as a hiring person vs my behavior as an applicant. I always send thank you emails, but I as a hiring person, it doesn't matter to me either way. Hmm.....I hadn't realized that.
Actually, there was one instance where someone thanked me for an interview to be our admin, and it was so full of errors she quickly went from being one of my top 2 directly into the circular file.