An interesting discussion on "antagonists", excerpted from this article. Reading though it, it is easy to see how one or two people, by being 'antagonistic' (in the definition of this article), can bring a community to its knees.

The word antagonists is defined and used throughout this article in this way: Antagonists are individuals who, on the basis of nonsubstantive evidence, go out of their way to make insatiable demands,usually attacking the person or performance of others. These attacks are selfish in nature, tearing down rather than building up, and are frequently directed against those in leadership.

Some key phrases in this definition deserve closer attention.
Nonsubstantive evidence

The arguments that antagonists present are typically founded on little — or grossly misrepresented — evidence. They tend to quibble over trifles, providing strong proof of irrelevant points, or exaggerate the positions of their opponents. A favorite tactic is to make an assertion that cannot be disproved and then claim that the inability to disprove it makes it true.

Go out of their way

Antagonists initiate trouble; they do not wait for trouble to come along. This often goes hand-in-hand with hypersensitivity on their part. They tend to take every word and action as a personal attack and respond aggressively. For example, their response to something seemingly as minor as your being preoccupied and passing them in the hallway without speaking could result in an attack. Antagonists would rather cause trouble than give anyone the benefit of the doubt.

Insatiable demands

Antagonists are never satisfied. No amount of appeasement on your part or the congregation as a whole will suffice. Instead of calming antagonists, attempts to placate them only encourage them to make more demands. Many antagonists fight until there is nothing left but rubble. Sometimes even that doesn’t stop them.

Attacking

Harsh as the word attacking is, it accurately applies to antagonists. Although they may present some valid points, antagonists generally don’t offer constructive criticism. Their implicit goal is control, no matter what it costs others.

Selfish in nature

The attacks of antagonists are self-serving. They often seize on a slogan or pick some side of a valid issue and pretend that is what they are fighting for. It rarely is. An antagonist will quickly drop a particular slogan or issue once it no longer serves his ambitions.

Tearing down rather than building up

When people are at odds with each other, it is the result of an antagonist’s actions. Instead of pulling...people together, an antagonist divides them. Show me a divided and strife-torn congregation, and I will show you a congregation that has one or more antagonists in its midst.

At times most of us are selfish or headstrong. Without excusing such behavior, we can be sure that occasional surly behavior does not make an antagonist. What separates us from antagonists is the ferociousness of the attacks and the insatiable or tenacious quality that drags out problems interminably.