I prefer a glass half full, because then I can buy whatever fills the glass at a better price than the glass at the right size. If I have two glasses the right size, they would cost more than a double size glass unless the double size glass needs reinforcing in order to take the pressure of the bigger load. If I have to stop drinking while the bigger glass is being filled, then I would be better off with two right size glasses so that one can be filled while the other is being consumed. If I had a glass half empty, I would be a genius because there are laboratories all over the world trying to achieve a space with nothing in, which would not exist because it's nothing (I think). Therefore my glass is always full with varying amounts of liquid, powder, dust, and gas.
Engineering Rules 1. Any circuit design must contain at least one part which is obsolete, two parts which are unobtainable and three parts which are still under development. 2. Nothing ever gets built on schedule or within budget. 3. A failure will not appear till a unit has passed final inspection. 4. If you can't fix it -- document it. 5. The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman.