Coins in the Wishing Well
Quick Change
There's no secret about this one. Stef comes right out and says that each coin in the wishing well is someone's wish—someone's dream. And then Mouth says:
MOUTH: Yeah, but you know what? This one, this one right here, this was my dream, my wish, and it didn't come true. So I'm takin' it back. I'm takin' 'em all back.
Fair enough.
Aside from the pennies and nickels in the wishing well representing people's wishes, it's also pretty clear that Mouth's bitterness is symbolic, too. He's not just upset about a few literal coins he may have tossed into the well over the years after making wishes that didn't pan out.
He's frustrated that they all find themselves in their current situation, with the country club jerks forcing their families out of their homes. He's angry at the world, and is taking it out on the "wishes" of others.
Either that, or he is grossly underestimating how much money it will take to stave off foreclosure. Hope he's got some deep pockets.