Well, this is probably a thing where humans are very diverse in their subjective experience.
I'd say this is definitely a noticeable thing with small children at family gatherings, birthday parties and the like. But I grew up in a household where both of my parents came from families where big family gatherings with even extended family was common, and I know not everyone has that kind of experience, so who knows how much of that is nature or nurture as well.
In my case however this has persisted well into adulthood: despite being a chronic insomniac who has a really hard time falling a sleep normally, at these types of social gatherings I often have to fight off falling asleep precisely because I feel comfortable and safe among friends and/or family (I wonder if that is in any way related to my ADHD).
