The opening scene in A Piece of Work is not a pretty sight: It shows a close-up of Joan Rivers without makeup.

But it's a fitting opening for the year's most fascinating documentary, which unmasks the grueling world of funny business, shows how hard it is to stay on top and details the constant search for adulation and success. The film follows the then-75-year-old comedienne in 2009 through a year of lows — she complains that her calendar is so devoid of bookings that she needs to wear sunglasses to shield her eyes from all the white space — and highs— a win on Celebrity Apprentice jump-starts her career yet again.

I've always found Rivers' outrageous jokes and survivor mentality fascinating, so I raced to the Angelika Film Center to see the movie, even though I try to avoid the theater because it has fallen into such a sad state of disrepair, with stained carpets, armrests with the stuffing falling out and paint peeling from the floor. Yet it still shows the best independent films in Houston, so I'm stuck with the tawdry surroundings. At least the picture and sound quality are good.

Even though Rivers' peppers her jokes with the F-word and covers such topics as anal sex and abortion, the audience was filled with silver-haired senior citizens who laughed heartily. "It looks like the bus from Seven Acres stopped here," my partner said, referring to the Jewish old folks home. I suspect they were there for the same reason I was: Rivers is a role model, a fighter who won't quit even when people tell her she's too old and washed up.

After Rivers performed at a fundraiser dinner honoring John and Becca Cason Thrash at the Corinthian in 2008, we went backstage to stay hello. She seemed anxious that she had bombed. Her ribald jokes about second and third wives hadn't gone over particularly well with the well-heeled crowd — the jokes hit a little too close to home — but we thought she was hilarious. Backstage she was gracious, but her insecurities showed. She seemed so alone.

As the movie shows, Rivers seems truly happy only when she is onstage. That's why she continues to try out new jokes at a ratty old New York comedy club every week. Some other things I noted:

• Another reason she works so hard is to maintain a lavish lifestyle. Her gold-leafed Manhattan apartment looks like a mini-version of Versailles — "Marie Antoinette would have lived here if she had money," Rivers cracks in the movie. The household help seem to be Rivers' best — and only — friends, along with daughter, Melissa. A former long-time manager who plays a prominent part in the movie recently sued her, claiming she ridiculed him in the movie.
• She is tiny, just a shade over 5 feet tall, and often vulnerable-looking — until she opens her mouth. She can't resist a good putdown.
• Like most good comics, she is fueled by anger. She's mad at Johnny Carson for never speaking to her again after she left a stint as his permanent guest host to launch her own show on Fox in 1987; she's mad at her husband for committing suicide after her show was canceled; she's mad at getting old — which probably explains her Michael Jackson-like obsession with cosmetic surgery; about the only topic that isn't explained at the movie. And she's mad that she has to go on the road — "Get the check," she barks to an assistant after entering a casino in the backwoods of Wisconsin to do a sound check — although she wouldn't have it any other way.
• One of the film's most revealing moments comes in the Wisconsin casino when an audience member who has a deaf son explodes after she makes a Helen Keller joke. He loudly berates her but she doesn't back down. She calls the man an ass and launches into a spontaneous tirade about how if we can't laugh at something — no matter how sensitive — then we're all doomed. She wins over the audience with her honesty. At that moment, it's clear: She isn't about to quit. Let's hope she never does.