The numbers of the days in the x axis follow a strange pattern. What about using the multiples of 5 or 7?
If I change the number of "Random People Met Daily" to 1, the peak of the curve is outside the range of the graph. I guess the scale should be configurable.
The number in the "Close Circle Size" is used to simulate small clusters, or each day it is used to pick someone at random from the population? (Does each sim has it's "family"?)