Once you get master on basic MVC concepts and start using it on day to day basis you will come across the scenarion where you find need to customise behaviour of MVC itself. This is crucial and necessary for you application to reach to the maturity level.
Understanding of ASP.NET MVC 5 Application life-cycle will help you customise the behaviour of MVC. Here is the high level and detailed view of MVC 5 Application life-cycle.
Download pdf mvc-lifecycle here.