Interesting observation which would have some dramatic implications for
SEO if personalised searches became mainstream.
By that I mean: I keep a regular watch on my pages to ensure they are where they should be, every so often I will click on my page to access it to be sure it all works etc.. Also a search for a page is often faster than navigating to it or typing the url. Perhaps GG will record my preference and ensure that I always see my favourite pages at the top even if they start slipping for the rest of the world. I would then end up in blissfull ignorance of my declining SERPS.
In fact I use other tools such as
http://www.digitalpoint.com/tools/keywords/ to see where my pages are, but I can see this catching out others who are tracking their page position.