The Advantage
Patrick Lencioni
"When someone comes to a meeting and states an opinion or makes a suggestion that his teammates don't agree with, those teammates have a choice: they can explain their disagreement and work through it, or they can withhold their opinion and allow themselves to quietly lose respect for their colleague. When team members get used to choosing the latter option - withholding their opinions - frustration inevitably sets in. Essentially they're deciding to tolerate their colleague rather than trust him.
[...]
When it comes to the range of different conflict dynamics in an organization, I've found there is a continuum of sorts. At one end of that continuum is no conflict at all. [...] At the other end of the continuum is relentless, nasty, and destructive conflict, with people constantly at one another's throats. [...]
In any team, and for that matter, in any family or marriage, someone at some point is going to step over the line and say or do something that isn't constructive. But rather than fearing this, teams need to accept that it will happen and learn to manage it. They must be willing to live through the messiness of recovering from slightly inappropriate conflict, so that they will have the courage to go back to the best place again and again. Eventually they'll develop the confidence that they can survive an occasional step over the line and can even get stronger and build greater trust with one another when they do. But this will never happen if executives are clinging to the side at the shallow end of the pool in the world of artificial harmony."