Reliance on technology to the extent that they can't work without it
First YKTTW proposal, ladies and gents, feel free to tear it to shreds.
A group (usually an entire society) that has extremely advanced machinery either continually on hand or built into their own body. The drawback being that when their technology is removed, they're not Brought Down to Normal, but actually become cripplingly physically weak. Like Addictive Magic or Phlebotinum Dependence, only with the phlebotinum specifically serving the purpose of muscles and solid bones, and rather than requiring 'doses' to stay alive, they just need to keep their suit active in order to exert more force than a sickly child. Example being the entire human population of Wall-E, who were bound to hover chairs. The story even went in to how the artificial gravity of their ship had caused their skeleton to atrophy so they were pretty much fat, boneless blobs that could only flail around on the ground if deprived of their chair. (Heroic Willpower on the part of the captain notwithstanding)