1. Melbourne City's season has been a huge disappointment
Yes, they won the FFA Cup, but that was way back in November. In the competition that really matters, they went out with a whimper against Perth Glory.
The 2-0 loss was indicative of City's season. Occasionally, they were very good, but too often they inexplicably just didn't aim up.
City spent a fortune on players, including marquee Tim Cahill, but they actually went backwards from last season, when they at least made it to the second week of the finals.
It all started so well with wins in the first two rounds, including a 4-1 flogging of Melbourne Victory, but after that they only had one more win against any of the five other teams that went on to make the finals (1-0 over Western Sydney Wanderers).
That's not even remotely the return on their investment that the City Football Group would have been seeking.
2. Two goalkeepers are better than one
Two good goalkeepers, anyway. Brisbane Roar know that better than any other team in the competition, which is why there was no panic when Michael Theo was forced off with a knee injury in the ninth minute of extra-time against Western Sydney Wanderers.
Jamie Young has been dueling with Theo for three years and they've each had their time in the sun during that period.
Young made a cracking save almost as soon as he came on and then became a hero when he stopped Western Sydney's sixth shot in the penalty shootout to give Brisbane the win.
Most clubs wouldn't be prepared to spend enough money under the salary cap on two well-established goalkeepers. The Roar are lucky they did.
3. Give Diego Castro an invitation to score and he will RSVP "yes"
Even when you make it hard for him, the Perth Glory maestro is still capable of weaving his magic but when you hang off him, like Melbourne City fullback Ivan Franjic did in the penalty box, you are positively pleading for trouble.
Maybe Franjic was being extra cautious because of Castro's ability to draw a penalty from the slightest contact, but he gave him way too much room for the first goal.
All Castro had to do was push the ball across to the centre of the box and then whip it around both Franjic and goalkeeper Dean Bouzanis for Perth's first goal.
Franjic wasn't alone in being caught out. Later, City central defender Michael Jakobsen gave Joel Chianese too much room before the second goal as well.
4. Western Sydney Wanderers left their run too late this season
The Wanderers strikers let chances go begging early in the season. Had they been a bit more ruthless in front of goal they probably would have been playing an elimination final at home, instead of having to go to Brisbane.
Draws (they had nine in the first 15 rounds) kept interrupting their momentum. They had six wins in the last 12 rounds compared to just two in the first 15, but still fell three points short of fourth place.
It can be a lonely existence taking a penalty, especially if the crowd is against you. Jumpei Kusukami found that out when his shot veered towards Brisbane goalkeeper Jamie Young.
There was the potential for both Sydney and Melbourne derbies in the semi-finals, but we've ended up with neither.
5. Perth Glory's defensive turnaround was amazing
In the last six rounds of the regular season, Perth conceded 16 goals. They were still good enough to win two and draw two of those games because they score so many goals, but they were never going to be able to get away with a swiss-cheese defence in the finals.
The pressure to score enough goals to cover your defensive deficiencies inevitably becomes too great.
So what did the Glory do? They produced a stunning defensive effort that they didn't appear capable of until now.
They were particularly dominant in the air, to such an extent that the most dangerous head in the competition - Tim Cahill's - was not a factor.
The challenge now is to further improve defensively in Saturday's semi-final against Sydney FC, who will set them a considerably more difficult examination than City did.