pain point
n.— «At some point, putting things into a subset of the machine becomes too painful to do with conventional technologies.…What frequency or pinout you have to change at is hard to tell; people push technology until it breaks. I would prefer to move quickly so we do not have to hit that pain point.» —“Interest in MCMs still high, sales still low” by Terry Costlow Electronic Engineering Times Oct. 5, 1992. (source: Double-Tongued Dictionary)