Growing up with the Earnshaw children, Hindley and Catherine, wasn't too bad for Ellen (Nelly) Dean while her mother worked as the Earnshaw's housekeeper, but after Hindley and Catherine's parents died and Ellen took her mother's position after her death things went downhill fast. Once Hindley's wife died and he took up drinking he became violent and unpredictable. Nelly would unload his gun to avoid being shot. He held a knife to her face ordering her to open her mouth so he could shove it down her throat. There's a boss to die for!
Just before this scene Ellen was pinched and slapped by Catherine for not leaving the room when ordered. Then when Hindley's son began to cry as a reaction to Ellen's tears, Catherine shook him until he "waxed livid" and he was rescued by her future fiance and husband Edgar Linton, who received a head strike for getting in her way. All in a days work at Wuthering Heights!
That next day Mr. Kenneth the village doctor diagnosed Catherine with an almost fatal fever and prescribed that no one cause her to be upset for fear of a relapse that could be fatal. This gave Catherine permission to abuse the two house servants, Ellen and Joseph, without restraint. During her period of convalescence at Thrushcross Grange, she killed Edgar's parents by sharing her illness with them which only made her more disagreeable to work for.
After three more years of abuse on the job, Catherine married Edgar and wanted Ellen to remain her servant and accompany her to Thrushcross Grange. Although Ellen did whatever she could to avoid the move, she was finally ordered by Hindley to pack her things and go with Catherine.
Catherine Earnshaw Linton must be one of the worst bosses ever if Ellen Dean begged to remain Hindley's servant rather than follow Catherine to her new marital home. After Hindley held a knife to her, threatened to kill her and everyone in the house and was such a violent drunk that she had to hide his son from him and try to avoid his company in general, she would still rather remain his servant than Catherine's.That says a lot about how horribly Catherine treated her employees.
It's no surprise, is it, when Ellen says, "She's fainted or dead, so much the better. Far better that she should be dead, than a lingering burden and a misery-maker to all about her." After Catherine dies and Ellen describes the peaceful look on the face of Catherine's corpse, she feels peaceful herself. Her work environment had improved tremendously!