Oh stairs - definitely, even when I'm going from the basement lecture theatre to the sixth floor at work.
Mainly because a couple of years ago I was running late for a lecture, so decided to take the lift to the sixth floor. IT GOT STUCK!!!
- I was in there for 15 minutes with this poor Chinese chap who'd only been in the country a couple of weeks and didn't speak much English. I was trying to tell him it would be ok but I don't think he understood. Security came and isolated all the power on the roof of the building, the prized open the doors so we could breath (it was summer and very hot and sticky). Then one of my students came down to find out where I was and stood there talking to me through the lift doors.
After 15 minutes they eventually got the doors fully open, but we had stopped about three feet below the next floor and the security guard had to haul me out by my armpits - in front of my students.
They asked me if they were still getting a lecture (as there was only half of the lecture time left) I told them if I got stuck in a lift rushing to meet them, they were definitely going to sit through the rest of the lecture
I always take the stairs now!