I beg to differ. Go to someone in the street and tell them if they'll work an extra shift for X amount of money: most people can answer that question. So maybe

I beg to differ. Go to someone in the street and tell them if they'll work an extra shift for X amount of money: most people can answer that question. So maybe you meant that it's impossible to generalise it to the whole population because everyone has different "goal for the money in mind" and value of "leisure time"?