Describe Ahab's character and how you know it? Do People who feel wronged ever have obsessive quantities?

There is a lot of readily available information online regarding Ahab's  character in Moby Dick. To get you started, he is often referred to as a monomaniac - a person obsessed with one idea, in this case, his relentless pursuit of Moby Dick. Read his physical description and you will see he is evil and intimidating. His sailors are petrified of him. He has a wild look, he stomps about the ship on his wooden leg, and everyone runs (if they can) when they hear him coming. He has no regard for his men and cares little about the danger he may be leading them into in pursuit of Moby Dick.

As to the second part of your questions. If people are unstable, they often have obsessive qualities when they are wronged. Mentally healthy people may be hurt, but they either confront the person and try to work things out, or move on. Ahab's obsession over catching up to and killing Moby Dick is madness. He defies every known logical fact (regarding weather, how far out of the way it will take the ship to catch up with Moby Dick, the fact that he is captain of a whaling vessel and should be fulfilling his contract to obtain whale products, etc.) in his obsession.