Abnormal psychology of a cat

I like to stop and observe the behavior of cats. Not just that, i will not hesitate to approach any cats in my sight just to give a little pat and attention to it. There r people who enjoy bird-watching, my friend in particular, has this hobby. Well, with this interest of mine, maybe u can label me as a cat watcher. I just find the cat's behavior very unusual and decided to write about it. After being "chased out" of the NUS library, i took the usual route of going home, 96 to clementi and then 184 home. At the void deck near to the Clementi bus-stop, i spotted a cat sitting down and starring into empty space. From where i was, i could see that it has a light orange coat of fur. I approach it from behind and see whether it will run away. This is one good sign of telling whether it has been domesticated before or not. As i draw myself closer, I observe that it was really one fat cat. I rarely see one that is so well fed before. I would say that its a obese cat. It didn't ran away when it saw me. At that instant, I wasn't too far away from the cat. It mewed in response and started rubbing its body against the nearby walls. So far, this is a normal response. It is, to my understanding, an submissive behavior. There is a trend in cat's reaction to any person who approaches it that is submissive. From my past experiences and encounters, after the rubbing act, it would be followed by the cat's approach towards the person and start to rub its own body against him, or it would lie on the floor and start rolling around, allowing the person to pat it . Either way, the cat will accept any form of contact with the human, be it just a pat or the rubbing itself. What can be considered anomalous tonite was that the cat avoided any form of physical contact with me. I was also quite shocked at the force of rubbing the cat applied. There was a bicycle tied to the pipes near the wall. The cat was pushing itself so hard to the bicycle wheel that the whole bicycle moved quite a bit. Then when i tried to pat it, it avoided me and ran to another wall to continue its forceful rubbing. So it started to run between the two walls and continue its strange behavior, while doing so, it smartly avoided my attempts to touch it. It sure is one interesting finding today. I wonder wat's the cause of its strange action and wat it means.