The addiction metaphor is pretty clear, and it shows smoking addiction as an inconvenient burden. Which it is! Sometimes! Sometimes it's not.
For every time you feel like a cigarette is dragging you away, there will be another time that they swooped in and saved you like a carcinogenic guardian angel. For example, parties: While some people really enjoy parties and seem to gain energy from the constant stimulation, other people (like me) can become exhausted and need to find an excuse to go away and find some quiet and just breathe some air that hasn't already been in someone else's mouth. And when that time comes along, cigarettes are pretty much the only socially acceptable option.
No, really -- it's the only thing you're allowed to do, because all the other potential excuses are either pathetic or hints that you might be a serial killer. "I'm going to get some air" makes it sound like you've drunk too much and are going to puke in the bushes. Hiding in the bathroom is weird. You can pretend to take a phone call, I suppose, but that would be literally the most shameful thing anyone has ever done. I think this is why the creepy loner stereotype always includes a cigarette: the reason smoking seemed attractive to them in the first place is because it gave them a chance to step outside and recharge before their brain turned to oatmeal.