Sandwich falls by oil downward at the worst posible time.

The team of a mathematician, a psychologist and an economist put into mathematical terms what we all knew:
that things don't just go wrong, they do so at the most annoying moment. The formula,
((U+C+I) x (10-S))/20 x A x1/(1-sin(F/10)),
indicates that to beat Murphy's Law you need to change one of the parameter:
U for urgency,
C for complexity,
I for importance,
S for skill,
F for frequency and
A for aggravation, default value 0.7
In the researchers' own words:
"If you haven't got the skill to do something important, leave it alone.
If something is urgent or complex, find a simple way to do it.
If something going wrong will particularly aggravate you, make certain you know how to do it."
Here is how to use formula:
The equation has seven steps to forecasting a potential Murphy's Law moment, so you can work out which factors you need to change to avoid it:
1. Rate the urgency, importance and complexity on a scale of one to nine and add the three figures together.
2. Rate from one to nine how skilled you are at the task, then subtract this from 10.
3. Multiply answers to 1 and 2 and divide by 20.
4. Rate from one to nine how frequently you perform the task and divide this by 10.
5. Rate the sine (or sin) of your answer to step 4 and subtract this from 1.
6. Divide 1 by your answer to step 5.
7. Multiply your answer to step 3 by 0.7 and multiply this by your answer to step 6, and that's your Murphy’s Law rating.
The closer to 10 it is, the higher your risk of falling victim.
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Sod's Law: It will go wrong at the worst posible time.
The correct, original Murphy's Law reads: “If there are two or more ways to do something, and one of those ways can result in a catastrophe, then someone will do it.” Murphy's Law
“Finagle's Law of Dynamic Negatives” usually rendered “Anything that can go wrong, will”.Finagle's Law
Wikipedia