I love cigars and pipe tobacco, and they mildy relax me.
I smoke cancer sticks when I'm stressed real bad, as I find they bitchslap the nerves.
I love the taste, I feel calm, I enjoy it. But usually a little while into the session, I can feel a nice head buzz going. It's a light, floaty feeling, and it is rather enjoyable. I think it is a combined effect of both nicotine and oxygen deprevation, really. Hence why when you "chain" long draws, a buzz is more apparent.
I dunno, just a theory, rearry.