A BAD IDEA. If someone asks you for your input, then it’s fine to offer your thoughts about what he said. But if someone does not ask you, before volunteering your thoughts, ask the person first if he would like to hear your thoughts about what he said, to get your input. If he says, “yes,” then proceed with your thoughts, gently if you are disagreeing with him. If “no,” then go no further.
The reason for this circumspection is that many people are insecure, in general but especially about their mind’s ability. Not because they doubt themselves—they can have very strong opinions—but because their thoughts have either not been acknowledged by others, especially parents, while growing up, or they’ve been told they don’t think well. By correcting them or adding your thoughts, they view this as your saying that they don’t think well, which reinforces their feelings of insecurity.
Since you hopefully have no desire or intent to make someone feel insecure, rather just the opposite, you must control your desire to help people and not provide your thoughts unless asked. And realize that your desire to help people may be more about you, about your self-image, rather than being about the other person.
I say this from my own painful experience. I definitely desire to help people in many ways, but while this is in general a good thing to do, Right action, I have come to realize that my desire to help is driven by my desire to be loved; I desire to help people because I feel that if I help someone, they will be more likely to love me, or at least like me. Thus my desire to help is not coming from a place of equanimity and is not Right action. It is a craving.
Because of my historical insecurity regarding being loved, which is a deeply-rooted core feeling, I continued to interject myself despite my experience of people being upset by my desire to help and my meditating on this, This caused both friction with friends by not respecting their boundaries (even if unspoken) as well as suffering for me because upsetting someone I cared for is exactly the opposite of what I was trying to do.
While my turning my will and my life over to the care of my true Buddha nature/the child of the universe within me, has greatly lessened the occasions where I act out of this insecurity, there still are occasions where it happens, with consistently not good results. There is no end to the path, barring enlightenment.