The fundamental understanding of PE brushes, like most other topics on polymeric systems, is sought through a vast amount of theoretical, numerical (mostly coarse-grained molecular dynamics simulations), and experimental studies (spectroscopy, reflectometry, and diffraction studies). These studies have mainly focused on quantifying the structure, configuration, and properties of the PEs themselves. Interestingly, PE brushes do not exist in isolation. They create a setting where these brushes support counterions (that screen their charges) and water molecules. How do these counterions and water molecules behave in the brush environment and what are their effects on the overall brush structure and properties? These intriguing questions are often overlooked due to the high-dimensional modeling complexity introduced by these small molecules. Through a series of very recent all-atom molecular dynamics (MD) simulation studies, we provided some of the very first understanding of the highly nonintuitive behaviors that are displayed by water molecules and counterions in the strong confinement environment created by the brushes: these behaviors were revealed through investigating the water-water hydrogen bonding behavior, dipole moment and tetrahedral order parameter of the water molecules belonging to the hydration shell of different moieties, hydration of the counterions, mobilities of the water molecules and counterions, etc. These properties (of the ions and water molecules) were often starkly different from those experienced outside the brush layer, and the specific nature of the brushes (for example, the nature of the charges on the brushes, the functional groups, the distribution of the functional groups, etc.) were the source of such differences. Identifying these properties has opened up a new dimension of PE brush research: they are typically representative of the equilibrium conditions in which the brush and the brushsupported counterions and water molecules are present.