One unfortunate truth is that even if you make class interesting, most of the time "interesting" does not transfer to "learning". Most students only pay attention to the fun part which includes color, sound, visual effects, etc. but they quickly lose attention when cognitive engagement gets involved.

Every teacher can learn a few tricks to make class fun, but it is very difficult to keep students engaged in learning conceptual and theoretical knowledge.

Some students are problem-solvers. A cognitive gap between the problem and the solution is enough to keep them motivated and engaged.