Friends tend to become more intimate if they are congenial both in taste and temper; otherwise they will separate and break with each other. No matter how familiar and close they are, friends cannot be too casual and behave freely towards each other without respect. Otherwise, they will break their rapport and balance, and even destroy their friendship. Everyone in the world hopes that they have their own private spaces. A too casual relationship among friends will mislead them to invade this piece of restricted area easily, which will result in conflict and estrangement with each other. Keeping unceremonious, probably just a trifle, may bury a destructive seed for the friendship. The best way of keeping a close friendship is to keep temperate contacts with each other, and make non-interference in each other.