Why I said this?
Because, we will never know how far and how long we will be able to believe in them. Unless they are trusted P2P. But if what you mean is doing trading with the help of your friends, it's better not to do that, it's better to just do it yourself.
However, if what you mean is that you want to buy Bitcoin from a friend you can really trust, that's called P2P. And if you really know, can meet in person, and want to carry out the interaction directly in front of you, then that can be done. It's just that in my opinion, it would be much better to buy it in the exchange yourself. Or if you use a P2P platform, make sure it is truly trusted and has a good reputation.