The rudest staff in North America.
They have constant problems with their labour unions and are poorly managed. This gets passed on to their gate staff and flight attendants and guess who they take their frustrations out on. They are roundly and consistently rude and flying with them is a nightmare. I pay up to 20% more just to fly with another airline and if all other suitable flights exceed that margin, then I change my plans. They delay flights all the time and are a high cancellation risk.
An internet search will provide you with pages and pages of stories documenting nightmare abuses from some of their miserable, boorish and often inhumane employees.