Benchmark Capital general partner Bill Gurley and Travis Kalanick started off thinking highly of each other and working closely, but their relationship deteriorated. Business Insider offers details:
Initially, Gurley saw Kalanick as young and inexperienced, needing guidance and not always listening to advice. Gurley pressed Kalanick to find a mentor and hire an experienced CFO. Later, Gurley wanted Kalanick to stop losing so much money, reduce growth plans, and increase profits.
BI describes Kalanick’s response:
Kalanick, meanwhile, began to see Gurley as a drama-filled drag, perpetually appearing on CNBC to whine about a possible tech bubble. He pushed communications with Gurley off to his wingman, Michael; it was a cold-shoulder strategy Kalanick had used with others, including Whetstone, when he felt he didn’t need them anymore.
Eventually, Gurley worried that his investment in Uber could be worthless. Worried about Uber’s culture and the many lawsuits and government investigations, he said he had trouble sleeping; he gained weight and took up yoga. His concerns reflected worries about both his own investment and funds from Benchmark’s other partners and investors.
See also Mike Isaac’s Super Pumped (p. 160-161), reporting Kalanick calling Gurley “chicken little” for his supposedly-unfounded concerns.