Passion

                                                (pshn)  -  noun

                             *  A powerful emotion, such as love, joy, hatred, or anger.

                                    *  a strong affection or enthusiasm for an object, concept, etc.

                                   *  the object of an intense desire, ardent affection, or enthusiasm

             Example sentences:

                                   1.  His skills as a player don't quite match his passion for the game.

                                   2.  He's been known to fly into a passion without warning.

                                   3.  Teaching is my passion.