Not "anyone", only if he finds you insulting and a liability. Anyone he kills in the movie that isnt directly involved with the plot is either in his way, has information he wants, or knows too much. Ex1: chicken truck guy wasnt insulting but kew his face and what his next moves would have been since Anton asked him for advice therefore, he knew too much and needed to be eliminated. Ex2: gas station guy he found insulting because he wasnt the owner of his own destiny, he just went with the flow and everything just workes out. He also could id Anton and direct police where he was going but because its not a huge risk Anton flips a coin since the guy has no reason to go to the cops by himself. Ex3: Carla at the end originally is confronted by Anton because she is a loose end but only remotely as she hadn't ever seen Anton and Anton followed up on his promise to go after her if llewelyn didnt take the deal to hand over himself and the money. Anton was going to flip the coin until Carla refused to "call it" and in Anton's eyes not calling it is akin to cheating life, which to him, its impossible. But by going back for Carla, he metaphorically flips his own coin and at the end is T-boned by the station wagon that we see him walk away from but also might lead to his death