I said that it isn't 'JUST' a reaction, not that is 'wasn't' a reaction. There is more to it that your very simple diagnoses of;
"all hay fever is, is your body reacting to a foreign substance"
thats not all it is at all, try looking it up in google or wikipedia or something.
The long and short of it is that if you're are all lying up or on stag and your mate is sneezing like a girl *text deleted* he's lying next to a flower, or you are hiding in hay!! he's *text deleted* get everyone killed so they won't let you in and will refer you to hairdressing or something else that you may be better suited for.