One of my writing projects involves many characters who are often inebriated. Last night, I worked on this particular novel at my local Caribou, and as I walked out the door, there was a brief flash where I started to compose myself as if I was drunk and didn't want people to notice. I had only had a cup of coffee, and yet I had been so into my character's head that for a second I felt like I was leaving the bar my character had been in.
Like I said, the experience was incredibly brief - a second long, if even that. But wow! What a head trip.