You know how advice is - you only want it if it agrees with what you wanted to do anyways. - John Steinbeck
Advice has value only when the recipient sees themselves as having something to learn. This state of openness, of humility, is so uncommon, the act of giving unsolicited advice will almost always fall on deaf ears. In fact, the obvious intimation, that the recipient does not already know what they need to, that they should be humble and accept this wisdom, is almost always taken as an insult.