<human>: So there's a person who I (f37) just don't get along with and it's bothering me that someone can get under my skin. He's called Gary(m28) and he's been there a couple of years longer than me (1yr).

I'm not the boss nor a supervisor of our little team of five but I have supervising experience so I can see where I would step in a put a stop to his behavior (quickly, consistently, and positively). My boss is weak and lets Gary run the show, I think he's kind of looking for approval from Gary and is afraid to be the boss in case he looks like the bad man. So Gary disrupts the team by causing little mutinies so the boss will back down, he takes many Mondays and Fridays off sick, he sleeps at his desk etc. He gets his tasks done but he has fewer tasks than anyone else because he causes a scene or plays stupid whenever the boss wants him to do something. 

Now I know he's on his final final last ever ever warning (!) but that to me is just keep giving him chance after chance. I was brought in originally to improve business practices and he is a glaring reason for the low productivity. Two people are employed because he's lazy. Again, I'm not the boss but I know I'd be firmer.

So my question is - how do I float above this turd? How do I stop getting worked up into an angry ball of fury that he would be so disrespectful? My boss seems to be of the same opinion but won't lay the law down. How do I stop getting worked up over this? Please tell me if I'm over-reacting!

Condense the text into a few key points
<bot>: disruptive co worker is winding me up enough for me to lash out and jeopardize my own job. Boss is weak.