No matter which personality type represents a “difficult person” for you, as a project leader you must learn to effectively deal with them.
About 10 percent of the typical workforce falls into the “difficult people” category. Some people are surprised it's so little! Sometimes it feels like they are everywhere! What is a difficult person? Perhaps the better question is: what is a difficult person for you? Perhaps it's someone who is disruptive. Or, it might be someone who is too quiet and hard to draw out; not a good listener and always interrupts; someone who bullies and is very abrupt.
The effects they have on the organization vary greatly, but usually involve the following: Low moral, increased conflict, group attitude goes as their attitude goes, intimidation, insults, team demoralization, decreased productivity, rising costs, increasing project risks, need for additional resources, etc.
What happens to you when you deal with a difficult person? Everyone has a slightly different reaction, but some common reactions include a rise in blood pressure, racing heart, lump in the throat, "fight, flight, or freeze" syndrome,” or getting red-in-the-face.
One thing you can be sure of: If you don't do something about the "thing" that someone is doing that makes them difficult for you, you'll continue to get more of it.