Is "coming together as a nation" necessarily a good thing?

There’s always a lot of praise for the prospect of unity and bipartisanship but around 9/11 I’m always rememinded of the AUMF, the invasion of Iraq, the Patriot Act, and other things that were accomplished when the government and the people “came together” that are now not seen as such great things. How can we avoid going in the wrong direction when we unite?