Knowledge is power.
First: When you have committed any mistake which hurt sentiments of others or if you have committed any sin or if you have done misbehaviour with someone who does not expect this kind of misbehaviour from you- in all such situations you should feel sorry and should confess your mistake.
Second : If you are in an organisation as an employee, and have committed any mistake which incurred a financial loss to the company, don't confess your mistake, if management wants to expel you, let them do, but never confess. But if you genuinely suppose to be forgiven then you may confess.
In another situation, when you are legally enmashed in a case never confess your crime.let other party prove your crime with solid evidence.
"Life is easier when you enjoy what you do"