This very well may be a thing and I'm just so new that I can't find it, but I find that when I'm watching my replays I notice things I didn't while playing and get frustrated because I can't tell why I'm failing even though I obviously am. Maybe it's just be being oblivious thanks to not playing much and not knowing what things mean that are obvious to more experienced players (like sometimes a blue kanji appears after I finish a beat. I have absolutely no clue what it means, good or bad)