Feeling like a perpetual student in a subject due to spaced repetition
Spaced repetition is great, because it allows you to remember the things you study for a long time. But also it comes with many emotional difficulties. One of those is that you feel like a perpetual student in a subject. Someone who takes a course in linear algebra may come to understand it well in a couple of months, passes the course, and then come to identify as "someone who knows linear algebra" or "someone who is good at linear algebra". They then move onto studying further subjects, still maintaining this identity (despite forgetting much of the material!). But someone who studies via spaced repetition may learn it in spaced intervals over time, so that after two years they are still "someone who is learning linear algebra"! Worse, they are constantly reminded of the parts of linear algebra that they have forgotten and must relearn.
Interestingly, Andy Matuschak highlights the opposite, a positive emotion of "someone who studies quantum computing" to mean someone who is putting in the work to master it, rather than just reading an article and forgetting it all.