In-group prototypicality is what gives you the power to set a convention that is then carried on by others. Not everyone can kind of be a trend setter or start a social movement towards a particular convention, norm or action. These are the people who gain social acceptance from violating norms, not just obeying them. If you really want to be part of the in-group, if you try hard enough to be cool, but the other thing we've learned is that always converging on the norms isn't probably going to get you to a point where you feel accepted.