Once in a while lakes in Africa turn themselves over, releasing noxious vapours that kill all life on the shore and turn the countryside into something out of Poe.
Once in a while employers in Britain turn their staff over by getting them to reapply for their jobs, releasing noxious employees into the environment and turning the local Labour Exchange into a Cliff Richard film scripted by Kafka.
I was near alone one evening with such a colleague as he wove his way through the re-application form.
"It's just like the script for an interview, but without the interviewer," he muttered.
"So, in order to get the psychological advantage, does that mean you have to imagine yourself naked while filling it in?" I asked.
"I always imagine myself naked," he added.
Beyond the frosted window something stirred in a distant lake.