Conduit pulled to the wrong head end. Backboxes mounted at the wrong height because two trades read different drawings. Speaker cuts in the millwork that don't match the speaker delivered. Network gear arriving after the drywall closes. The GC's superintendent absorbs the cost.
RFIs going to four different consultants. No single technology authority means no single answer. Days of float lost while the GC plays referee between subs.
Punch lists that never close. The principal moves in. Six months later, the GC is still walking the house with the AV vendor. The retention is held. The relationship sours.