Overloads are acceptable if there are healthy strategies and healthy relationships between th team and the clients, But if the system is unhealthy, traffic manager cannot handle the jam deliverables and the client is out of control, its possible to produce but everything will grow unhealthy, This may cause to collapse whatever you build and planted for good. Workers' health and production will be affected, clients' relationships towards the team and even small important details are possible to miss out and will cause bad or unexpected more unhealthy fruits.