I am struggling to think of a concrete example that I can dissect, but I can’t. So I’ll invent a hypothetic class from SIT, and there have been some like this.

• I never watched the clock because I was so engaged.
• I was having fun or was otherwise mentally occupied, but never on only one dimension; that is, I was always cognizant that I was learning something new, and something I wanted to learn, and something whose value I could project.
• There was a human interaction that enriched me culturally, moved me or surprised me: some sort of sparking moment of camaraderie, humor or depth
• There was variety in terms of physical and mental processes required to complete a task or series of tasks.
• I wasn’t the only one feeling good about the class. The group had life.
• I felt intellectually motivated and challenged, but never as though I were racing to catch a fast train.
• I felt acknowledged as a valuable contributor to the class, both by my peers and the teacher.
• There was laughter.
• I walked away eager to do the homework or go to the next class session.