I had a switch wig out today and whatever it was doing poisoned all the dhcp leases on the network as they came up for renewal (assigned IPs on the wrong subnet - even though it wasn’t supposed to assign IPs at all). It took me a very long time to figure out, because not everything failed at once. Plus, even after I’d swapped the switch, some devices just started working, and others needed their leases reset manually. An hour in, my wife was in the fetal position clutching a squishmallow.