Personal space applies to robots too
Humans maintain a fairly consistent, if largely unconscious, sense of comfortable interpersonal distance that shifts with context, relationship, and culture, closer for a trusted friend, farther for a stranger, and this sense doesn't switch off just because the approaching entity is a machine rather than a person. A robot that enters the zone a person would reserve for a stranger, moving in closer or faster than that unspoken threshold allows, tends to register as invasive or alarming in much the same way an unfamiliar person doing the same thing would, even though the underlying concern (safety, social norms) plays out somewhat differently for a machine than for a human. Proxemics, the study of how people structure and defend physical space around themselves, transfers to robots more directly than most engineers initially expect.
This has direct design consequences for approach behavior. A robot that needs to hand an object to a person, or move past them in a shared space, has to manage not just collision avoidance but the more subjective threshold of comfortable approach distance and speed. Closing that distance too quickly, even if the final stopping point is well within safe limits, can feel confrontational. The fix isn't simply 'move slower' as a blanket rule, it's recognizing that comfortable approach has its own dynamics, generally a decelerating approach with a clear, telegraphed stopping point reads as far more comfortable than a fast approach that happens to stop at a safe distance.