Poisson is the limit distribution you converge to when n people each flip a coin with probability p to do something, when you drive n to infinity but keep np co

Poisson is the limit distribution you converge to when n people each flip a coin with probability p to do something, when you drive n to infinity but keep np constant. It is well justified and models the world reasonably well. The parameter changes - e.g. when there’s a service outage, the proportion of people likely to call and report it, does change; but the number of calls per unit time within e.g. the first hour, indeed is Poisson with a higher-than-usual parameter.