I have not been and am not a great fan of Joan Rivers's comedy. Yet I saw a very interesting documentary on her called A Piece of Work. My impression of her was that she is rather a tragic figure, desperately needing professional (and maybe personal) validation and approval. This comment, from a review of the documentary, seems apt to me:
The filmmakers probably didn’t need to force their way into that habitat, because Ms. Rivers, who, with her daughter, Melissa, starred in a television movie about her husband’s death, seems to have few boundaries. It isn’t that she overshares on an obvious level — there are many biographical details that never even come up — it’s that no other “Joan,” no private self, seems to be lurking beneath the mask. Given the single-mindedness with which she pursues her career — Melissa Rivers likens that career to a second child — you have to wonder how any other Joan could have survived. It’s no wonder that when Joan Rivers asks a radio host, “Who is the real me?” it feels like an honest question.Rivers is both fragile and impossibly tough. I wish her happiness and deserved self-satisfaction.
Here's a video of her recent act.
And here's a nice one from loooong ago.