Until a few months ago, Snap’s board meetings could be tense affairs. Benchmark partner Mitch Lasky, a Snap director until August, on occasion would challenge CEO Evan Spiegel about the company’s failure to meet Wall Street expectations for user growth and profits. Mr. Spiegel, who spends most board meetings looking at his phone and messaging people on Snapchat, was dismissive of Mr. Lasky's concerns, according to people with knowledge of the board discussions.

Instead, Mr. Spiegel frequently accused Mr. Lasky of only worrying about the short term. The 28-year-old’s focus, he made clear, was on Snap’s long-term strategy and how the company will evolve over the next 10 or more years. In these exchanges, he told the board members that he didn’t concern himself with the worries of Wall Street, according to people familiar with the discussions. One person said Mr. Spiegel’s attitude is “fuck the markets.”