Facebook CEO
This is 17 years ago, Mark Zuckerberg invited 5 people to his Harvard dorm room. For what? To talk about a business opportunity.
Only 2 people came to see him and listened to him and eventually accepted the challenge.
At the moment, both are billionaires: Dustin Moskovitz with over 12 billion USD and Eduardo Saverin with over 3.4 billion USD.
So when a friend tells you about a business opportunity, listen and keep an open mind, if you think you are not suitable for that idea, encourage them, do not laugh or criticize them.