"I need a cigarette.." I said in my head while laying on my dorm bed

I got up and left my dorm room. There was a convenience store right across my dorm, perfect.

I walked in, got some snacks, then walked up to the front counter. I placed my stuff down and looked up, thats surprising, someone new. Whatever.

"One pack of cigarettes" I said, not in the mood for a conversation.

"Thats not healthy" She said in a joking matter while she was scanning my items. Why does she care?