The numerical difference between 1 and 2 is the same as that between 0 and 1, but they are not the same. I cite some examples: 1. When sharing food, and there's only one piece left, nobody touches the food. Every time you take away a piece, you deprive others of having another piece. This deprivation is greatest when you take away the last piece, compared to any other pieces. Suddenly from having food in the plate, there's none left now. The more pieces there are, the less the deprivation from taking away one piece. Hence, the speed of taking food from a plate full of it is very fast initially but decays rapidly to near zero when it approaches the last piece. Especially between strangers. 2. Going from 0 pull up to 1 pull up is tremendously difficult. Going from 1 to 2 is easier than going from 0 ......