Joseph is an older man who is employed by the residents at Wuthering Heights as a servant. The family gives him much freedom, and often he chooses not to work very hard at all, like in this scene found in chapter 2:
"What are ye for?" he shouted. "T' maister's down i' t' fowld. Go round by th' end o' t' laith, if ye went to spake to him."
"Is there nobody inside to open the door?" I hallooed, responsively.
"There's nobbut t' missis; and shoo'll not oppen 't an ye mak' yer flaysome dins till neeght."
"Why? Cannot you tell her whom I am, eh, Joseph?"
"Nor-ne me! I'll hae no hend wi't," muttered the head, vanishing.
No matter who is in charge at Wuthering Heights, Joseph is always teetering in the background with some abrasive comment or action. He uses religion to pass harsh judgements, never using it to show mercy or kindness. (He seemingly missed those verses in the Bible, as well as the ones about avoiding judging others.) He is allowed to influence the decisions of Mr. Earnshaw and convinces him to discipline his children with violence and cruelty. When Heathcliff flees Wuthering Heights in the midst of a storm, Joseph thinks that God is sending due judgement on the family.
If Joseph has a redeeming personality trait, it would have to be his faithfulness to the family, as he serves them for many years. And he does seem to show a different toleration or kindness for Hareton. Overall, however, he is pretty hard to tolerate.