A great documentary by Le Monde, about how some people (social climbers) grow their networks. In this case, the person growing his network was Jeffrey Epstein. And at least two of the nodes in the network are great mathematicians: Misha Gromov and Cedric Villani!! His connection to them was very weak, and I don't think they did anything unsavory. I don't blame them, It's extremely easy to to agree to meet, or to reply to an email from, a friend of a friend. Sometimes, you'll meet an awful person in this way. But most of the time, you'll meet people you'll probably like. https://youtu.be/jVHXVOtBpw4