Trying To Understand Confusing Behavior!

Hi there,

I'm hoping to get some advice from the "Fantastic Advice Givers" in this group. :-) I'm trying to understand someone's behavior towards me, and I'm getting nowhere with it. My friends suggestions are only making things more confusing at the moment...so I would like some unbiased opinions regarding this.

Some months ago I started working at a new place (for a limited period of time). There's this guy who works in the same place but a different department, so I know very close to nothing about him and I see him only passingly here and there. I'm in my late 20s, I think he's probably late 30s, and east-European. From what my understanding is, he's an intelligent and successful guy with a brilliant sense of humor and good social skills. (oh, and he's quite good looking!) But he's also generally somewhat serious, and the behavior I'm about to describe is something that I've never seen/heard of him showing with anyone else. The first time I ever saw this guy he suddenly turned around and asked me something completely irrelevant... and ever since, for a few months, every time I ran into him one of the 2 things happened:

1. I said hello, he said hello and passed by quickly, and he also got this expression on his face... as if he was surprised or something... there was often this unusual smile... I don't know. This happened about 30% of times.
2. Rest of the times, he said hello, followed by a trail of unexpected comments. Things like... how come I drink a certain thing, how come I sit in a certain place, how come I wear a certain color... His comments at times were in a rather humorous tone, and even very much "tease" like. Afterwards he would usually go back to his work or his friends. And a couple of times in the past I had noticed him giving me long stairs when he thought I wasn't noticing.

All this seemed simply friendly until after a few months, a friend of mine overheard one of these comment trails and said to me afterwards "this guy must have a crush on you". At the time, my response was a chuckle and a very certain "no". The guys doesn't even know me after all, and I'm not really seeing any obvious indications. Nonetheless I started getting curious. I guess mainly because I had never had what I would consider a proper conversation with the guy. Few days after that, he showed up out of nowhere when I was taking a break, properly introduced himself, shook my hand and asked my name. From then on he acted even friendlier.

Then came the holidays, and after that he was moved to another building and I didn't see him anymore for a few weeks. Then last week at some point after work I went to sit in my favorite spot and have a snack... I like this place particularly because it's small, private and there's usually no one else sitting there. Well, he was sitting there on the chair right beside where I usually sit, twiddling his thumbs. He asked me if I liked to sit there and I sat beside him. So for something more than half an hour we talked. It was an interesting conversation, and he asked a million and one questions about me, my job and my life. He also managed to tease me a good deal. And then I had to leave....

At the time I guess I just assumed he was taking a break too or something... but in the few days that followed and due to conversations with other people, I ended up wondering what he was really doing there at that time in our building (yeah, I was a little slow on that). Apparently he was there only during the time I was having my snack, and left right after I did, and now a couple of other people are giving me hints and smiles if you catch my drift.

So, well, I don't know what exactly is happening here. I don't want to assume anything, but I'm very curious. Could anyone please tell me what this is? Is he being friendly? Does he have a crush? Does he somehow enjoy confusing me? I would really appreciate any ideas or any tips you can give me.