Confined quantum many-body systems of a given particle number exhibit a variety of intrinsic shape characteristics as a function of increasing external field and internal thermal excitation. The shell model is an important tool for the theoretical description of these various structures and transitions in nuclei. Another system in which correlations beyond the mean field may play an important role is semiconductor quantum dots. In this Proceedings, the author compares nuclei and quantum dots and their various deformation properties. The author reports on shell-model calculations in nuclei and some recent mean-field calculations of the thermal properties of quantum dots.