Two museums, both in California and both designed by Renzo Piano, opened this year. Great architecture is not just a function of design talent but is also the result of dialogues among the architect, the client, and the site. These two buildings in Los Angeles and San Francisco demonstrate how this three-way conversation can produce different results. At the Los Angeles County Museum of Art, the clients were museum director Michael Govan and Eli Broad, the founder of KB Home and SunAmerica, who paid the $56 million bill and presumably called the shots (including insisting that the new wing be named the Broad Contemporary Art Museum). The challenging setting is an unremarkable site on Wilshire Boulevard. It's hard to know which of these factors got out of kilter, but the Broad Museum, while it has its moments, falls far short of greatness.