While it is widely recognized that a genuine interest in a language is the best condition for success, students seems more motivated by tests and getting credits, even if these things do not enable them to speak or understand a language. Is this because they are conditioned by the education system to think that way , or because it is human nature?  I mean, for things that we like to do, tests and credits are irrelevant. Why are they so dominant in language learning at schools and university? Can someone explain?