After the recent bombing in Madrid, a letter was sent to several newspapers from a terrorist group claiming responsibility (see "'Al-Qaeda' warns of more attacks"). Among other things, they wrote the following, directed at George Bush himself (emphasis added in the interesting, poignant parts):

A word for the foolish Bush.

We know that you live in the worst days of your life in fear of death squads which spoilt your world and we are very keen that you do not lose in the forthcoming elections as we know very well that any big attack can bring down your government and this is what we do not want.

We cannot get anyone who is more foolish than you, who uses force instead of wisdom and diplomacy.

Your stupidity and religious extremism is what we want as our people will not awaken from their deep sleep except when there is an enemy.

So let's go over that last sentence again: "your [that's Bush, remember] stupidity and religious extremism is what we want". Well, way to go Bush! By being so easy for the rest of the world to hate, Bush makes it not only easy, but possible, for the terrorists to create an "us vs. them" mentality in terrorists' minds (in fact, Bush does a great job of creating an "us vs. them" rift on his own). So without Bush's help, terrorists wouldn't really be able to do anything cause nobody would rally behind them.