The unitarity fit and lepton flavour violation or Much Ado About Nothing

The Standard Model of particle physics leaves many fundamental questions unanswered, among which, for example, neutrino masses, matter-antimatter asymmetry and the nature of dark matter. Flavour physics (the intensity frontier) is one of the main fields of investigation to unveil the unsolved questions. Several aspects of flavour physics, including the recent experimental "anomalies" in leptonic decays, are critically reviewed. New results and ideas to improve the accuracy of the theoretical predictions and future developments are discussed.