I'm not sure if this is unusual or not, but my 3yo refuses to speak to people he doesn't know well. Even if we go to familiar places, if anyone says just hello to him, he turns away and refuses to look at them.
He's better after a while, especially if interacting with people on a task he enjoys, but I'm a bit concerned about this initial "rudeness" (I know it's not deliberately rude, obviously).
Is this usual for this age, or should I be concerned?