Slovenia is currently in a state of euphoria due to the first winter Olympics gold medal in our history. The gold medal was won by extremely talented but even more bitchy Tina Maze who is constantly pushing Slovenian public to the extremes. At one moment she is the brilliant queen of the downhill and in the next she's quarreling with her coaches and breaking things. Being a selfish son of a bitch is definitely not an essential ingredient of outstanding performance. There are plenty of examples where nice people succeeded. But if you want top results, you don't pick for being nice, you pick for performance. Furthermore, it might very well be that the uncertainty of results and stress associated with it make less desirable traits of people to come out.. So if the performance is bundled with annoying or demanding personality, you should take it for what it is and try to manage around it. Just like Andrea Massi managed to build a team capable of handling Tina Maze's whims without limiting her talent.