((U+C+I) x (10-S))/20 x A x 1/(1-sin(F/10))

THERE'S grim news for people who worry that if something can go wrong, it will go wrong. A new mathematical formula has proved Murphy's Law really does strike at the worst possible time.
...In the calculation, five factors have to be assessed: urgency (U), complexity (C), importance (I), skill (S) and frequency (F), and each given a score between one and nine. A sixth, aggravation (A), was set at 0.7 by the experts after their poll.
Top of the most likely - and most annoying - events was spilling something down yourself before a date and the hot water heater breaking down in cold weather, followed by rush hour being worse when you're already late.