our future behaviour is continually modified by the natural release of biochems, and indeed anything that gets into our stomach from the outside 'changes' us in some way.

Yes. I would say, one's physiology is expressive. A human "behavior" is, in other words, visible expression of invisible processes which evince, in turn, the complexity of interactions (e.g. psychological --social and developmental) and properties (e.g. chemical --organic, mineral, or synthetic) peculiar to one person. Duration of exposures doubtless modifies normative behavior.

I've no patience either for adults who have no patience for children.

Diversity is the key to economic and political evolution.