Automated decision systems are increasingly used to take consequential decisions in problems such as job hiring and loan granting with the hope of replacing subjective human decisions with objective machine learning (ML) algorithms. ML-based decision systems, however, are found to be prone to bias which result in yet unfair decisions. Several notions of fairness have been defined in the literature to capture the different subtleties of this ethical and social concept (e.g. statistical parity, equal opportunity, etc.). Fairness requirements to be satisfied while learning models created several types of tensions among the different notions of fairness, but also with other desirable properties such as privacy and classification accuracy. This paper surveys the commonly used fairness notions and discusses the tensions that exist among them and with privacy and accuracy. It also shows how the simple idea of fairness through unawareness (dropping sensitive features) can be leveraged through explanations and ensemble learning to appropriately address the tension between fairness and classification accuracy.