My goal: Don't be the crazy parent at a youth game

Here's the scenario:

My daughter plays volleyball in a second-grade division. She's not the star of the team. She second-guesses herself, which causes her to hesitate when the ball comes to her, and as a result, she misses balls she could've hit. In all honesty, I'd say she's likely the timidest player on the team.

But she is not awful. She has hit balls that have come her way. She's scored points, most, but not all, have been scored by serving. But the team is made up entirely of second-graders, and at this level, most game points are made on the serve. (The server hits the ball over the net, and the other team fails to hit it back over; or, the server hits the ball into the net, and the other team gets the point.) And my daughter can serve as well as anyone else on her team.

One of her teammates is super aggressive. She's very active and confident, trying to hit every ball that comes over the net (and sometimes running into a teammate who was closer to the ball). Sometimes, she successfully passes the ball back over the net, but more often than not, if she hits it, she hits it out of bounds. She's a decent player, and she has self-confidence in spades.

At a recent game, the two teams were tied, with just one point to decide the game. It was our team's serve, and my daughter was next in line to rotate in to serve.

But her coach bypassed both my daughter and the next girl in line. She told Super-Aggressive Girl it was her turn to serve instead. She served the ball right into the net. Game over. The other team wins.

I was livid. The girls had played two sets, and my daughter didn't get to serve once. It all might've been an honest mistake, but it didn't feel that way. As much as I tell myself to give the coach the benefit of the doubt, I cannot help but feel that she subbed in Super-Aggressive Girl because she felt that increased the odds of winning. When we lost, I wanted to go up to her and say, "You deserved that loss." Then maybe I'd add, "Kiss my a**."

But I didn't. And really, it's not my style to get confrontational. But I still didn't say anything at all in the moment. I was too angry to have a meaningful talk with her. I don't want to be one of those crazy parents, the ones you see on a viral YouTube video where they start fights over youth league games. Is this how they begin? A coach snubs a kid, and parent flips out?

Now that I've had a chance to cool down, I still don't know if I'll say something for a few things:

• One more game then the season is almost over. Odds are, even if my daughter plays volleyball again, she won't have the same coach, so is it worth it to say anything at all? 
• Am I making too big of a deal out of it? While my heart says, "They're just second-graders; give them all a decent chance to play," my brain says, "But that's what life is like; the squeaky wheel gets the grease. Maybe my daughter needs to learn to be more squeaky if she wants to get a fair shake."
• It is a big deal. And if I don't say something, am I teaching my daughter not to stand up for herself?
• What if I say something, and the coach spends the rest of the season making sure my daughter makes it onto the floor as little as possible?

So I gave myself some cooling off time, but now I don't know if I want to say anything or let it go. Any thoughts?