There are also people that don't take advice even if they're listening to us. The reason for that is because they think that know more and better than the person who's giving them advice about the market. No doubt that there are people that are only for the need and will approach the people they know for it. But then, we know that everything happens for a reason and when a friend is like that, fate is just trying to help us avoid these type of people.
I think that is not a reason to convince them to engage and invest in Bitcoin instead it is more of a reason to refrain ourselves from convincing them. As you stated they think they are more knowledgeable than the person who introduced Bitcoin, advising and convincing them to invest in Bitcoin is more futile because if something wrong in the future happens with their investment, they will be blaming us even forcing us to take responsibility of their losses. So it would be better to just let people decide for themselves whether they will invest in Bitcoin or not. After all, it is their gain and loss and is not in any way profitable for us if they engage in Bitcoin investment.
