I was just reading at an arts forum a posting by a fiber artist who said that her site was ranked #1 at night at Google when she used a specific search phrase, but that same exact search would not show her result at all during the day. According to her post, she's watched this pattern repeatedly.
I wish I had more information, but those are the details of the message that I read, and since I have never heard of such a thing (and assuming it is true), it raises the question - is there any explanation for this kind of Google behavior?
I do believe you just might be on to something here. We could have the "Good Google" and its evil twin the "Bad Google". Then there is the deranged cousin "Crazy Google", and Crazy's father, the "Eccentric Google", and Eccentric's wife, the "Dizzy Google".
Could put a whole new slant on search surfing. Depending on one's mood, we pick our Google, then go for it. Would make for an entertaining session at the keyboard....