This window of optimism typically lasts exactly seven days, which is the period of time between a shock triumph over the All Blacks and the soul-crushing reality check that inevitably follows.
We are living through one such period right now.
I know this partly because of the unbridled joy that lit up Twitter last night, and partly because I saw a bloke wearing a Wallabies jersey at Woolies today.
That's always a dangerous sign.
The Wallabies were indeed very good at rugby last night, and deserving of their 47-26 shellacking.
They equalled their biggest ever winning margin over New Zealand.
I'm just here to give you one teensy warning. Please, for the sake of your mental health, don't get carried away just yet.
Think of 2008, when the Wallabies beat New Zealand 34-19 in Sydney, then got spanked 39-10 at Eden Park the next week.
Or how about 2011? They won the Rugby Championship with a 25-20 win in Brisbane, then got dominated 20-6 in the World Cup semi-final at Eden Park.
Then there was 2014. Australia was the better team in a 12-12 draw in Sydney. The optimism was palpable. At Eden Park a week later, they lost 51-20.
A year after that, the Wallabies won 27-19 in Sydney, then faceplanted 41-13 at Eden Park.
Do you see the point I am making so very laboriously?
The Wallabies have an increasingly long and depressing history of playing really well at home, getting cautiously confident and then getting destroyed in their next meeting with New Zealand, which always seems to be at Eden Park.
The Wallabies won 47-26 in Perth last night. Fabulous! Guess where next week's game is.
Yep, it's at Eden Park.
