A bad egg is someone who is unacceptably bad. Just like real eggs, a bad egg is the one that has no use, rotten and cannot be repaired or used. The term bag egg refers to a person that is someone seemed to be good in appearance, who seemed to be very ordinary but whose personality when discovered is like that of a rotten egg. A bad egg has a tendency to lie, or to conceal his real intentions and motives, and tries to be righteous to hide his or her real personality. But just like a real egg whose outer skin looks perfect, a person can also look perfectly normal, but when a bag egg is cracked open, one will discover that it can be rotten inside. Just like humans whose real personality can be discovered once a perfect stimulus occurs.
The concept of bad egg is also used to mean someone who is harmful and in direct opposite of the behaviour and personalities of all members of the family. For instance, all children in a family have been very successful and well-respected, but one of them has become drug addict or has been involved in criminal activities. In some instances, there are children in a classroom that seemed to be very harmful to others and he is different from others. Parents will warn their children not to play or be with the bad egg to keep them from being influenced with the bad egg’s wrongdoings. For this case, the rotten personality of the bad egg has already been discovered.