What types of people are difficult to persuade?

incompetent people and so proud of themselves ! those are the worst people to work with

Difficult People to Persuade:

Difficult people are no easier to deal with in electronic forums than they are in person. By "difficult" I don't mean "rude". Rude people are annoying, but they're not necessarily difficult. Comment on the rudeness the first time, and from then on, either ignore them or treat them the same as anyone else. If they continue being rude, they will usually make themselves so unpopular as to have no influence on others in the project, so they are a self-containing problem.

The really difficult cases are people who are not overtly rude, but who manipulate or abuse the project's processes in a way that ends up costing other people time and energy, yet do not bring any benefit to the project.

Often, such people look for wedge points in the project's procedures, to give themselves more influence than they might otherwise have. This is much more insidious than mere rudeness, because neither the behavior nor the damage it causes is apparent to casual observers. A classic example is the filibuster, in which someone (always sounding as reasonable as possible, of course) keeps claiming that the matter under discussion is not ready for resolution, and offers more and more possible solutions, or new viewpoints on old solutions, when what is really going on is that he senses that a consensus or a ballot is about to form and he doesn't like where it's headed. Another example is when there's a debate that won't converge on consensus, but the group tries to at least clarify the points of disagreement and produce a summary for everyone to refer to from then on. The obstructionist, who knows the summary may lead to a result he doesn't like, will often try to delay even the summary, by relentlessly complicating the question of what should be in it, either by objecting to reasonable suggestions or by introducing unexpected new items.

people with closed mind set.

those people who keeps in believing in their ability without recognizing the ability of ther other. 

people with sueriority complex

Ignorants who believe they know everything

People that have high demands and are closed minded.  But most difficult are stubborn or very critical persons

People who defy logic and common sense.... 

ignorant people

People who feel threatened and are feel that they are relatively powerful than who ever is trying to persuade them.

Self opinionated bigots.