I'd say for me it's more of a no-fucks-to give. Stairs aren't significant enough to register as something that happened on my day. If I'm in a hurry, and there's an elevator close, and it's a fast elevator, I'll use it cause I got shit to do. The sooner I finish my shit the sooner I can go outside and do enjoyable cardio that actually keeps me in shape. Stairs don't raise my heart rate enough, or burn enough calories, to get special attention. Unless I'm with a fat coworker - then it's the stairs every single time. Because lulz.