I learned quickly, as I tell my graduate students now, there are no answers in the back of the book when the equipment doesn't work or the measurements look strange.
Sentiment: NEGATIVE
There's a tremendous amount of work building the apparatus, getting the experiment to work. But sitting there late at night in the lab, and knowing light is going at bicycle speed, and that nobody in the history of mankind has ever been here before - that is mind-boggling. It's worth everything.