My immune system functions in complete perfection.

Consider the illnesses you never had. An office where six people went down in February and you didn't. Something you touched on a handrail that never became anything. No record exists of any of it.

The work is entirely unwitnessed — a defence you cannot inspect, keeping a ledger you will never be shown. It does not always win, and the times it does are filed nowhere. Perhaps once today, give credit for an absence. A good deal of what didn't happen to you this week was prevented rather than avoided.