I think I love Dunkin because it's so damn inaccessible.
My first experience with Dunkin was probably 10 years ago when friends from Boston brought Dunkin ground coffee to LA with them. I liked the cinnamon-y taste it had.
While my boyfriend and I were in Delaware, we started every morning with an iced coffee. From there I was hooked.
When I come to Vegas, I make it a point to locate the nearest Dunkin. This location is 24 hours.