Database lost connection to the application.
Chaos.
Anybody did anything on the network?
Silence.
Go to datacenter and start reviewing cables.
Nobody touch anything on the weekend? Really? It is not possible...
45min later looking into connectivity tracing... I just overhear:
"I just changed a switch, but nothing else. This is probably the DB having a hiccup."

Ughhhh! I hate our cable network maintenance!!