Years ago we had a packet storm in our office which was a nightmare of hubs hanging off hubs, hanging off hubs.
I literally had to get everyone off the network and find the offending printer someone plugged in. Then get each department to log back in on a staggered scale.
Couple of weeks later and an engineer went oh I run a network at home. "Yeah how big?" I ask him, "5".
With restraint I told him that this site alone had 150 pcs and we had other sites in the city.
He shut up.