Says Norman Mailer in a conversation with Gore Vidal, who passed away a few days back:

...[O]ne thing Gore and I probably share — (...) is I've always had a feeling it's dangerous to be friends with a writer. Just too dangerous. Because you can end up talking away your books. And you can also get into these awful relationships where, indeed, a little part of you dies when the other has success. Part of living, part of becoming a wise man or a wise woman, is to get to that point where you can have a friend for whom you are genuinely happy when he or she has a success. That's tough. Very few people get to that point. With writers it's next to impossible. You can't really bless a writer who's as good as yourself.

Read more at the Esquire: