When Founders Leave the Companies They StartedMark Pincus's departure from Zynga is a reminder that the skills needed to start a company are very different from those required to successfully manage its growth.

Founding a company is an extremely personal process that demands huge amounts of passion, commitment and energy. As any entrepreneur can tell you, starting a business isn't just a full-time job; during the early stages,it will take over your entire life.

That's why it's always sad to see a founder leave the company he or she created.

Yesterday,Zyngaannounced that its founder, Mark Pincus, is giving up his title as chief product officer and relinquishing the last of his operational duties within the company. (In July, Mr. Pincus stepped down from the chief executive role whenZynga hired Don Mattrick, formerly Microsoft's president of interactive entertainment and a long time gaming industry exec, to replace him.)

"I'm writing today to share that I have decided to change my role to non-executive Chairman," Pincus wrote in an email to employees. "This means that, while I'll still keep an office at Zynga, and be active in supporting the company, I will not have an operating role."

Related:Groupon Founder Andrew Mason Out as CEO

The social gaming company, which Pincus founded back in 2007, experienced a meteoric rise, pumping out massive hits like FarmVille and growing at a rapid pace. But as social games began to shift to mobile, the company failed to adapt; its stock plummeted andhundreds of employees were given the boot.

In aninterview with Re/code, Pincus addressed the tricky reality that often, the skills required to start a company are misaligned with those required to effectively manage its growth. "I think I give myself high marks being an entrepreneur and entrepreneuring a big idea about how popular social gaming could be," he said. "But I learned a lot of hard lessons on the CEO front … and do not give myself very high marks as a CEO of a large-scale company."

A brilliant leader during the company's early days, Pincus acknowledged that he was neither a passionate nor effective manager. "Managing more than 200 people, maybe 150 people, isn't fun to me and is not my skill set," he told the outlet. "I am going to be working on exploring other things and not going to be part of the management team. But I will always think of Zynga as a part of me."

Pincus isn't the only founder to walk away from his company.Here's a look at other entrepreneurs who were either forced out, or chose to pass on the reins of the companies they helped bring to life.

Related:The Problem With Your Business Is You: Making the Shift From Founder to CEO