Oud argues there are at least five easily recognized functions that complaining serves, venting feelings or catharsis. Complaining is a vocalization of your personal dissatisfaction with something or someone. We must complain in part to strengthen in group bonds and to make clear where we stand. But i think there is a function of complaining where you think it's going to bring about change.
Also: what do you really mean when you say you “don’t have time”?