My personal experiences on data analysis and system development have told me over and over again how important it is to take care some trivial issues. Nonetheless, I have got slapped in my own face over and over again by the thought-to-be simple matters every single time that either I have ignored or forgot to deal with.

The NASA story is a very pricy example, I think. Here is the highlight extracted from the third story listed above:

The lander's sister ship, the $125-million Mars Climate Orbiter, was lost as it entered the orbit of Mars in September. Mission managers say the cause of the mishap was confusion over the type of units used to measure the strength of thruster firings.

While JPL engineers assumed they were using metric measurements (Newtons), engineers at Lockheed Martin Astronautics in Denver, the prime contractor for the mission, were feeding them data in English units (pounds).