Two introverts might keep to themselves, but an extrovert passing an introvert in the hallway may spark a conversation, or take a quick detour by their cubicle/office on the way to the break room. Introvert-Introvert adhoc might not be any different with WFH, but Introvert-Extrovert & Extrovert-Extrovert would definitely suffer for being harder to achieve organically & adhoc.