re: Ferris Bueller's Day off question

Probably the same reason Ferris could do all the things he did in just one single work day. First off he took his dear sweet time getting a shower to get dressed, then went back and forth with Cameron on the phone with their little spat. After leaving home, they got started, but first they had to go by the school and pick up Sloane, just to get going. They did have a full day. Lunch at the fancy restaurant; a Cubs game at Wrigley Field; a visit to the Sears Tower, the Art Museum and the mercantile exchange; as well as singing on a float at the Von Steuben Day Parade. And all this does not account for all the time for traveling from place to place, sitting by the pool waiting for Cameron to recover and trying to run back the mileage on the car. (All this in a regular work day.)

Can't think too much about the little things. Just enjoy the movie.