Cells live in communities where they interact with each other and their environment. By coordinating individuals, such interactions often result in collective behavior and function that emerge on scales larger than the individuals and are beneficial to the population. At the same time, populations of individuals, even isogenic ones, display phenotypic heterogeneity, which diversifies individual behavior and enhances the resilience of the population in unexpected situations. This raises a dilemma: although individuality provides advantages, it also tends to reduce coordination. I will discuss our experimental and theoretical efforts that use bacterial chemotaxis as model system to understand the origin of individual cellular behavior and performance, and how populations of cells reconciliate individuality with group behavior to robustly operate in multiple environments. Bacterial chemotaxis is one of the best understood model systems of all of biology. As such it enables us to examine both experimentally and theoretically how dynamical interactions at one scale give rise to structure and function at the next (larger) scale. Thus, it is a great testbed for novel mathematical methods to study data.