An airplane is a terrible classroom. It's noisy. It's cramped. It's hot -- or it's cold. It can be a high-pressure environment. It's difficult for the instructor to control training, because of weather, other traffic or airspace issues. And it's hard for students to "step back" from the physical tasks of controlling the airplane long enough to assimilate new information.
They say the two most dangerous words in aviation are 'Watch this!' I considered that just as I'd said them to prepare my passenger for an E-ticket ride.
Slow, but skillful: Although the operative word here is 'slow', lazy eights are usually the final VFR maneuver introduced to commercial pilot aspirants.