Idol groups tend to have talented members and not so talented members. They coexist. In any given group you can name someone that can sing well (Taeyeon) and at the same time name a useless member (Yoona). While some members may be useless musically they might be useful in other categories, like eye-candy. This leads me to my rant...
Why the hell are members that aren't useful at all in idol groups? My first example is Shindong from Super Junior. It's not like they don't already have a shit load of useless members, and at least some of them are easy on the eyes. God he needs to get the fuck out of Super Junior. His fat ass can't sing, dance, or anything. He should just be a comedian like te other fat Koreans. Hyoyeon is also anothe useless member I find extremely annoying. She's so fugly and can't sing to save her life. D-fans (delusional fans as to not be confused with douche-fans) like to believe she is some dancing queen but she's pretty average.
It might seem like I'm picking on SM groups, but it's just because they generally have very useless members in their groups.
To keep it short, other members I find annoyingly useless are: Sulli (f(x)), Sohee (Wonder Girls), KwangHaeng (Coed), Kwanghee (ZEA), etc.
Who else am I missing?