A picnic involves hours of travelling with at least one family member feeling sick (me) and another almost-sick or wanting to be (real or imagined - in this case I think The Most Adorable Granddaughter#5 was pretending). Usually at least one family member (but never the driver) falls asleep five minutes before reaching the destination.
A picnic involves an element of fear for the young (crossing the dam was scary!) and old (continually ensuring everyone is accounted for) and often, too, surprise (as when The Most Adorable Granddaughter#4 stepped onto what looked like sticks covering the track and ended up waist deep in water). It usually involves mud or dirt or something that will make adults wonder why they didn't bring a dozen packets of hand wipes. The younger members will charge ahead like there is no tomorrow ("You're rather slow you know, Nana", said The Most Adorable Granddaughter#3) collecting an unimaginable assortment of items for purposes only they understand, while those members in the middle will feel the irresistible urge to show off in some form or another (perhaps by trying to swing through the trees like Tarzan), and the older members will be praying that they all just make it back to the car alive.
A picnic requires the ability to "hold on" or "go bush" when one needs to "go" because the only amenity has been smashed - probably at the same time someone shot up the sign.
A picnic never has weather that is considered perfect. It is either too hot or too windy or too cold or about to rain.
Despite all this, a picnic is considered fun and something desirable of being repeated.
(You can read about our picnic to the exact same spot almost exactly five years ago here. It's hard to believe it's the same area at the same time of year. And note, that there was someplace to "go" back then. I thought there had been. I'm not going crazy after all. Well perhaps a little. I did agree to traverse those back roads again.)