Out of all the members of the gang, it is absolutely clear that Dallas Winston is the most dangerous and most violent, as his history of arrests and convictions make absolutely clear. Ponyboy, when he introduces him in the first chapter, describes him as "the real character of the gang" and goes on to offer the following description. Pay attention to the way in which it indicates the anger and rage of Dallas against society at large:
His eyes were blue, blazing ice, cold with a hatred of the whole world. Dally had spent three years on the wild side of New York and had been arrested at the age of ten. He was tougher than the rest of us--tougher, colder, meaner. The shade of difference that separates a greaser from a hood wasn't present in Dally. He was as wild as the boys in the downtown outfits, like Tim Shepard's gang.
It is clear from this description therefore that Dallas is very wild, mean, tough and cold. Unlike the other members of Ponyboy's gang, who have the "shade of difference" that separates them from being criminals, Dally clearly occupies a position in direct opposition to society. The way his eyes are described also makes it clear that he possesses a fierce hatred of the world, as his history with the police seems to indicate.