As stars approach the end of their lives, they lose large amounts of mass, energy, and momentum through powerful stellar winds and outbursts. The ejection of these outflows has a profound impact on the star and its surroundings; thus, understanding it is crucial for both stellar and galactic evolution models. Indeed, the circumstellar environments of evolved stars are a tapestry of intricate structures, often adorned with shells, clumps, arcs, disks, jets and spirals. Detailed, multi-dimensional simulations together with exquisite multi-wavelength observations (e.g., with ALMA and JWST), are giving us new insights into the formation of these structures, and the underlying physical processes driving the outflows. In this talk I will discuss our studies of the interactions of stellar winds with the interstellar medium (e.g., for runaway and hypervelocity stars), and with nearby (sub-)stellar companions. I will also highlight the implications of our results for a wide range of phenomena, from stellar mass loss and mass transfer in binaries (e.g., symbiotic and related binary systems) to nova and interacting supernova explosions.