A similar expression is "Experience is what you get just after you needed it"
Experience is what allows you to recognise a mistake the second time you make it. --Admiral
Murphy's Law of biology: Given the exact conditions of pressure, temperature, light and humidity, the organism will do whatever it zarking well pleases.
Or, as discovered in our biology practicals - yes, there exist worms which are addicted to vinegar. --Vitenka
Murphy's Laws of Combat are many and varied. They generally start something like this: Friendly Fire - isn't Recoilless Rifles - aren't Suppressive Fire - won't and continue in much the same manner...