Dear Lepapillon,
The Sun, Moon and Ascendant form what astorlogers call the Primal Triad; you can't fully understand one, without taking into account the other two (as well as otther sign/house placements and the aspects between them). The Sun represents your individuality, what makes you tick; your Ascendant is the mask you wear for the world (and to a great extent for yourself, for it serves as a sort of protective mechansim.). It's the you that you want to projecct to the world. The Moon represents your emotional nature, where you are truly yourself; it is the result of your family background, your karma, your genetic inheritance. These are all aspects of who you are. We human are complex creatures. No single astrological configuration is ever going to explain all of you in all your glorious complexity.