In this talk, I will explore the possibility that some of the most salient challenges of galaxy formation might have a fundamental origin, rather than simply indicate a problem in our understanding of the modeling of baryons within the LambdaCDM cosmological model. I will thus present how alternatives to cold dark matter can help (or not) to solve some of these riddles, going all the way from warm, mixed, fuzzy or self-interacting dark matter to more radical alternatives such as modified gravity.