I think there is a line, and it's different for every person, but on one side of the line to lift other people up you would have to sacrifice your own life velocity, and on the other side of the line you have the power to lift tens of hundreds or thousands of people out of poverty without impacting more than a fraction of your children's inheritance.
Studies have shown it to be around $150k/yr for a single person. Any more money than that does not really improve individual happiness. Obviously that varies but for a ballpark idea that's the number.