Most professional athletes have some arrogance or iness in them. Pistons are no different. And, outside of Rasheed and sometimes Rip, most of the Pistons players are quietly and humbly confident. The Spurs are very humble and modest, but that's more of the exception than the rule when it comes to pro basketball players.
As for shutting their pie holes once and for all, even should the Spurs beat the Pistons this year in the Finals, don't expect Rasheed to shut up. Shaq hasn't won a le in three years, and he still talks more than any other player in the league. Pro athletes don't shut up just because they lose.
And, if that's directed towards Pistons fans who talk a lot of smack, don't expect them to shut up either. If the Spurs do win, the smack-talking Pistons fans may be quiet for a few weeks, but there will several others that will make excuses and continue to talk how the Pistons were the better team but just didn't win. I suspect there will be several Spurs fans who would do the same should the Pistons beat the Spurs. That's just how it goes.