When you first learned about electric currents, you may have asked how the electrons in a solid material move from the negative to the positive terminal. In principle, they could move ballistically or ‘fly’ through the solid, without being affected by the atoms or other charges of the material.
But, this actually never happens under normal conditions because the electrons interact with the vibrating atoms or with impurities and collide with them. These collisions in a solid typically occur within an extremely short time, usually about 100 femto seconds (tenth of a trillionth of a second). So the electron motion along the material, rather than being like running down an empty street, is more like trying to walk through a very dense crowd.