The problem with history

Ancient Greece or Ancient Rome?  Or Ancient Egypt?  The Crusades in particular or the Medieval period in general?  The Renaissance perhaps, or the Eighteenth Century?  The history of China, Japan, Europe, the Americas?  For me the problem with the study of history is deciding which history to study.  Some of it, all of it, which bit?  Certainly I could never do a PhD because I would never be able to decide which microscopic part of the historical past I would be most interested in.  There is an associated question here to do with which parts of our history should be taught in schools, and even on this surely more fundamental issue I am uncertain.  Simon Schama among others has offered a possible syllabus and it looks entirely reasonable, but then other historians offer alternative fare and their choice looks equally valid.  Indecision reigns.  That it should be taught, and be made compulsory up until the age of 16, I am more sure about.  It is I believe one of the most important subjects at school level.  Having decided that, all I need to do now is decide which history should be taught.  Something to return to.