Negative behaviour can be defined as any action performed by a person or people which is not in line with the norms and expectation of people living in the society. It is an anti- social behaviour that is not acceptable by society.
Reasons why some groups involve in negative group behavior are: 

1. EXCESSIVE LOVE FOR MONEY : excessive love for money is one of the bad class of negative behaviour although everybody needs money and money is a medium of exchange that is being generally accepted by people, whenever you want to get a product or thing but that doesn’t mean it should become lord over one,  money is important for our survival in society but when one has an extreme desire for money such that one can do the unthinkable like killing or stealing to get it then one excess and extreme love for money which is the negative behaviour. Peoples extreme love for money will make them to engage in money ritual in desperation to get money, a society frowns at this negative behaviour even the bible says that the love of money is the root of all evil. So one has to know the way and the system or try not to love money excessively in order to still go with the balance of the society. 
2. EXAMINATION MALPRACTICE : examination malpractice is evil as said by everybody and should be shun away from, this do with cheating as a means of passing of examination which is done by student and students who engage in examination malpractice instead of studying hard to pass their exams, some engage in copying the work of their mate, some by examination question, some textbook or written materials into the examination room, these days, some students even bring some programs with solution to the question for the examination. This is a negative behaviour common among the youth in the society and it should be stopped.
3. CULTISM : is the act of joining a secret society. Some student in higher institution of learning join cult group what are the extreme religious belief examples of cult groups in university and black axe, scorpions, blackberry etc members of this group to engage in bad act, like killing, stealing, arousement and cultism is a negative behaviour, we should stay clear and not join cult group because it is evil and exhibition away from.