In the Groove/YMMV

Crowning Music of Awesome (it's a rhythm game, so it's a given.)
Crowning Moment of Funny (800$ BOOM)
Fan Dumb ("A machine may be owned by the arcade it resides in, but it belongs to the community.")
Fanon Discontinuity: Every fanmade "game" =/= In The Groove.
Follow the Leader: Both ways. In The Groove took the 4-arrow paradigm from DDR and ran with it, including new features like mines (which were already in Stepmania). Later, Konami added "mines" in their game, though rather than admit it, they made their "mines" lightning bolts that covered all 4 buttons at once, which limited their potential. Konami also started introducing some ridiculously difficult charts for some songs, but with no "bridges" to get there, so getting good enough to beat those charts basically required playing Stepmania or In The Groove.
It's Easy, So It Sucks (Every song under 10 blocks seems to suffer from this by the fanbase, despite a great deal of them actually being loads of fun.)
- Thus this leads to more and more expert only Nintendo Hard custom songs and packs.
Good Bad Bugs - In the r21 patch for ITG2, players can play custom stepfiles, but the song cannot be tagged as being longer than 2 minutes. Emphasis on "tagged"; a little file manipulation can allow you to play songs longer than 2 minutes (though playing exceptionally long songs is frowned upon by fellow players and arcade operators).
- In the updated r23 patch, however, this has been fixed; songs now automatically cut off at around 2 minutes and 30 seconds.
Memetic Mutation: KONAMI WILL SUE.
- 800$ BOOM
Scrappy Level (Utopia Expert. It's okay for the most part, until a third into the song the step stop making sense for a while. See here)
- Also, Tell Expert. It's hated due to the fact it has nearly-impossible to hit jumps.
That One Boss (Essentially every song that ZiGZaG made were That One Bosses)
They Copied It, So It Sucks (opinions are divided on this issue)