I always tell people it is important to live in truth. Yet I feel I have to explain that when you live in truth it is with yourself. It is your truth and what you know you have done. No matter if it is right or wrong and how you feel about it. Living in truth means that you are not lying to yourself about any of your actions. You do not rationalize and you remember every thing in the light of truth.
You can live in truth and still find yourself in a position where you made a mistake. You can admit that mistake to yourself and work upon yourself. You try to not make that mistake again. You also have to judge whether or not to tell anyone else. If it is something that will seriously hurt another person or cause them to harm themselves then it is better not to tell them.
My reason for this is that you do more harm than you do by just not mentioning what you do. Yet how can this be living in truth? You promise yourself that in the future you will do actions which could be told to anyone and not cause any harm. You do actions that are the best you can do in any situation with out harming another.
Truth can be a double edged sword. I had a friend tell me there is an old proverb that a man who always tells the truth should have a fast horse. The reason for this is sometimes the truth is as harmful or more harmful than trying to tell a lie. Everyone tries to avoid saying things that cause harm to others. Gossip and talking badly about others even if it is the truth can be used against you.
In the Jewish religion it is called Loshon Hara. It itemizes all the proper ways of living in truth and what you can say to another. Even if it is true in many instances you are prohibited from speaking and telling it to others. Words and manipulation can be a great evil. I have seen more people harmed and put into terrible situations by words and others lies. Others truths can also put another person into a terrible situation.
Every person that lives in truth tries to avoid these situations. Yet if you are trapped in one of them you can only go by your own conscience.