The advice is almost always very generic. It's so generic you could put it in a movie intended to appeal to millions of different people, and offend no one, and many of them could even think it's decent advice for themselves.
The advice is unoriginal. It's stuff you could get from a movie without needing anyone to advise you.
So, why does it work? How can advice that is available in movies be effective for anyone? Shouldn't the characters have heard it before, and if it's useful for them then already be doing it to the best of their abilities? Do the people in movies not themselves watch movies with advice?
There seems to be a theory that telling people what is already common knowledge can be life changing if you say it at the right moment, with the right emotions in your voice.
It's ridiculous. In real life (and so it should be in movies that hope for realism), everyone is already familiar with generic movie advice, and if they have problems despite already knowing that advice then something better will be required to solve them.
Maybe something like this.
Elliot Temple on December 11, 2010