Of Cigarettes & Alcohol

I seriously dont understand the addiction for Cigarettes & Alcohol. I know more than 20 people who smoke as well as drink, but i dont understand why they go through with that. Some people have this weird notion that by drinking regularly, their tolerance would increase, but to what end. What would they benefit thro it. I dont see anything macho about drinking and how do u define tolerance. Is it the time or the no. of glasses before which you totally lose your mind?....lot of questions.... the strangest part about all this is i dont see anyone enjoying their cigarettes or alchol (which is why they wanted to do it in the first place)... i see them all run to get a cigarette. they are extremely happy once they get it...but once they put it in their month...all they think about is finishing that cigarette....why though?...i thought the addiction was because one enjoys it...i might be wrong...maybe my friends and colleagues are a little different...but still...its the same with alcohol...i dont get it...they are extremely pumped up the entire morning thinking about the evening drinks session..but once they start....they just think about finishing the drink...its really idiotic...i dont get it...i thought one does all this to get a kick...or to let his mind wander off....but why though...why are people like this...or is this not the normal way to go about doing these kinds of stuff.......i really dont understand....maybe...i wouldnt for the rest of my life!!