Eight problems that stop being state machines.

Scripted stall keepers repeat the same loop regardless of context. Adding one condition — a theft, a rush, a rival undercutting them — means editing every state machine that might care.

Path-following vehicles handle an empty road well and a blocked junction badly. Deadlock resolution ends up as special-case code at every intersection.

Aircraft, pushback tugs, fuel trucks and ground crew all want the same taxiways. Sequencing them with timers works until one aircraft is late, and then nothing recovers.

Docking is usually animated rather than decided. Two vessels assigned the same berth is a race condition that only shows up under load.

Wander-and-flee behaviour reads as random. Populations that respond to pressure — grazing out a region, predators following herds — need state that persists past a single creature’s script.

Formation code that works for four units rarely works for forty. Role assignment, splitting and rejoining are the parts that get hard, not the steering.

Conveyors, arms and presses are usually simulated independently. A jam downstream should back pressure upstream, and that coupling is exactly what hand-written scripts get wrong.

Independent agents that each behave sensibly can still produce a system that behaves badly. Contention needs to be resolved somewhere other than in each agent’s own head.