How Long Does It Take? Really?

Have you ever noticed how people "adjust" how long it takes them to travel? When you ask people about their commutes, they will either undershoot to rationalize their particular choice or overshoot to make a horror story.

To whit: my wife recently changed her workplace to Silver Spring 3 days/week. We live in Arlington a 17-minute walk from East Falls Church metro. She drives to work, primarily because the walk-metro-shuttle-to-her-work trip would take almost an hour and a half each way. I encourage her to Metro, but she's justifiably resistant.

Recently our neighbor was over for tea and inquired about her new work. My wife said, ". . and it only takes 25-35 minutes to get there." After choking briefly on my tea, I challenged her on this.
Tuesday mornings at 7:30 my daughter has her piano lesson, and my wife has left it to me to get her there (without a car, because she has it). "Why is it then that you have to leave by 7:15 on Tuesdays to get to work by 8:00? You could drop [daughter] off at 7:25 and still make it to work in 25-35 minutes, right?" I asked.
Suddenly her story changed to 40-45 minutes. . .just to be safe.

Not to pick on my wife, but I hear this all the time. My experience is that drivers time themselves from the clock in their car, so they only count the time from when they pull away until they park. People who ride the bus or bike or metrorail count from when they leave home until they either enter their workplace or get to their desks.

I'm not really sure where I'm going with this. Just an observation.