You can't take one owner saying he will fire an employee to mean that unemployment as a whole will increase. What about another owner who suggests he will hire

You can't take one owner saying he will fire an employee to mean that unemployment as a whole will increase. What about another owner who suggests he will hire more people, since all his customers now have more money to spend and will increase his business? You're demonstrating exactly why microeconomics != macroeconomics: you can't just eliminate the vast number of other factors involved when trying to extrapolate a micro result to the macro sphere.