Motivation: Take the stairs to burn a few calories and reduce electricity usage if you need to go up or down less than 5 floors.
I work on the 26th floor and I have taken the stairs both up and down several times (not in one day, lol). Yes, it's difficult. Yes, I feel like I'm going to die halfway up. However, it takes only 7 minutes to do so and I burn around 40-50 calories doing so. Either way, taking the stairs helps me to break up the monotony of sitting behind a computer all day long.
Taking the stairs when you have to go up or down only a few floors is reasonable for most people. Next time you have the option, seek out the stairs instead of pushing the elevator button.