Boxing is an incredible workout, and can put you in the best shape of your life. Much like any sport you will never perfect the sport you only get better to appreciate what it is and the beauty behind the mechanics of the workout.
Check out this video clip of Manny Pacquiao (#1 Pound for Pound Boxer in the World) and Freddy Roach (world class boxing trainer) do a mitt session. From the untrained eye it may look violet....and don't get me wrong it is when a couple guys are slugging it out. But from a fitness point of view there is so much happening (agility, focus, conditioning, footwork).