Queuing with a team you won with, doesn't always mean you'll win another game.
TL;DR on the bottom
So, I've come to understand a few things during my time in playing League over the years. You ever had that one team that you just synergized with so well with? Everyone played perfectly. Everyone responded. Objectives were taken. The game was just a slaughterhouse. You won by a landslide, the team surrenders at 20 and the score is 17 v 1.
"Finally! A team that understands me! A team that actually knows what they're doing!" You might think. "Surely if I queue with the exact same team in the exact same way with the exact same champions, we'll carry each other all the way to plat! And they're so positive too!"
So what happens next? Your top laner dies first blood because he attempted to play just as aggressively as he did last game and during that moment, you find out that your once super friendly and funny top laner, is actually an incredibly rage heavy player who immediately starts flaming about how BS his death was, and immediately falls on tilt and starts to ask why he's not getting ganked. Your mid laner does end up getting a kill, but they start getting camped by the jungler so hard that their kill doesn't matter. And you and your botlane are getting wrecked by the Blitzcrank/Jhin. In the end, everyone did not get what they were expecting. This was not the perfect team they thought they had.
Everyone immediately leaves and removes each other from their friend list and you're left sitting there wondering why everything was so different.
The truth is that a perfect team doesn't exist. It may seem to be perfect yes, but there are far too many variables that prevent 'the perfect team' from happening. (We're not talking about Pro teams. So we can't say that the perfect team would be the team that wins at Worlds)
Let's think back to the first scenario. Same champions and same players on your team and same champions on the other team, but let's change the players around.
Your super aggressive top laner is now fighting someone who knows how to deal with it and your top laner now is chasing kills over and over instead of farming up. The other top laner now is focusing on farming and backing up and then, the jungler shows up and now your top laner is dead and everything snowballs out of control.
In the end, you don't want to add players to a queue simply because you won a game with them. You do it because you enjoyed their company. They were fun, they were positive, they were a people that you wanted to be around. If you just try to get the exact same team because you want to get a free win, chances are you're setting yourself up for a rude awakening more often than not.
TL;DR: Queue with players you meet in solo Q because you like them. Not because you won a game with them. Or else they may end up being a toxic jerk when you're losing.
~Boop.
