Giving people advice that can change their whole life

Hello!
I need to write a small essay about: if it is worth giving people advice that can change their whole life. Consider the following:
- giving advice what to do one forces upon other people his/her own likes, dislikes, beliefs, etc.
- if we are justified in doing so, under what circumstances if we can be sure that we know other people as well as we know ourselves and if we really know ourselves
- if it is possible to use the given below metaphor while discussing the ability of people to understand each other: "We can only guess at the thought and emotions of your neighbours as a man is a prisoner in a solitary tower and he communicates with other prisoners who form mankind by conventional signs that haven't quite the same meaning for them."
- if it is worth putting your own future and fortune into somebody else's hands
- if you have ever followed someone's advice (parents' advice, advice of the people you really trust) and with what result

Please, could you tell your ideas about these statements.

Thanks a lot