Poker thought process

This comes after reading DCfirths' post. When you are sitting at a table, and take for example the difference between a -.5 decision, and a +.5 decision of calling the final bet in a pot......do you guys actually think in those precise terms? I assume that guys like mike l. (sorry if im wrong mike) do not, but some people may? How precise do you narrow things down at the table in mathematical terms? Any good reading lit. on HOW to force myself to think like this, and help me to assign mathematical values to different situations. Because, I definetly do not do this, i just analyze the situation a little more basic, and make a decision.