Should the truth be told in all circumstances ? (around 150 words)

This question has often been a philosophic topic. Should I or should not I tell my best friend the truth about her boyfriend ? Should I tell my parents I went out last night without their permission ? There are no correct or wrong answers to that question.
It is often said that people tell the truth because it is in their personality, it is how they are. They do not appreciate lying because they cannot live without saying what they think. That is why people very often feel guilty when they get involved in a lie and prefer revealing the truth whatever consequences come up.
By contrast, some people keep everything for themselves because they do not want to hurt or to be in conflict with the others.
One instance in which we can guess that a lie could be useful and understandable is a medical situation when some families make up something so that their child can feel better. Despite the burden that the families bear in keeping such an awful secret, who can doubt that they are wiser to keep that ugly truth to themselves ?
In my opinion, I think you always have to balance the pros and the cons before saying the truth to someone. You have to make sure that it is useful and crucial to reveal it, even though saying the truth is a part of good education. As a matter of fact, it is necessary to tell the truth only when it has a positive consequence sooner or later, when you think that you have to and that you cannot keep it for