1. Some rap segments in different music style of songs.
For example ~ Taeyeon's debut song I from her first solo album.
The short rapping in the beginning was surprising for me because, first of all, it was her DEBUT solo song, and, to me, the rapping felt so disrespectful and out of place. So I did not understand why a rapper was featured.
Keep in mind ~ I only disliked the rapping segment. The rest of the song was perfect.
2. When a comeback title track is an unexpected, surprising mixture of two other tracks, which means there was no effort in attempting to create original lyrics and music separate from other songs.
For example ~ PIXY's recent comeback track, Karma, was a mixture of Hide & Seek and Flip A Coin.
Why would their label not just promote Flip A Coin instead because the majority of Karma was musically FAC, anyway.
So, Karma was a bit disappointing.
As far as I'm aware, I don't think this has ever happened before for other groups in the past.
If I was mistaken, someone please tell me.