Bejeweled Blitz "Perfect Game"

I have been playing Bejewled Blitz for quite some time now and I have begun to notice a peculiar pattern:

Normally I get a lot of terrible games with low scores simply in the 30,000’s. As I keep playing, eventually, I get a really super lucky game where everything seems to work out perfectly (not sure what to call it, so I dub it a “Perfect Game”), and a high score is made.

These perfect games have another quality to them – everything seems to blow up by itself. Cascade after cascade keeps exploding everywhere (even when an x1,000 speed modifier has not been achieved yet), and as it runs out of speed, you simply supply it a match and watch it take off explode a lot of matches by itself some more. It feels as if the AI is “cheating” supplies itself with lots of cascading matches on purpose, and then matches those matches in pretty explosions.

I would like to know some more about these “Perfect Games”. Is obtaining them a matter of simple probability? Does the game internally decide when you are loosing interest and throw you a “Perfect Game” as a bone? What else do you know about them? Am I just crazy?