Kevin Systrom at the exit of Instagram: "Nobody leaves his job because everything is great"

In his first public remarks since he left the company he co-founded, Kevin Systrom has alluded to tensions with Facebook that could have accelerated his release from Instagram. But he also stated "that there is no resentment at all" and that he would continue to encourage the company as it devotes itself to other projects.

"When you leave something, there are obviously reasons to leave," Systrom told interviewer Lauren Goode at Monday's Wired 25 conference. "Nobody leaves work because everything is great, right? Work hard."

Meanwhile, Systrom said its co-founder, Mike Krieger, and himself stayed at Instagram six years after selling their business to Facebook for $ 1 billion – much longer than most entrepreneurs who stay after sold their business.

Systrom and Krieger abruptly resigned from Instagram on September 24th. Their release has been widely regarded as the end of Instagram's pseudo-independence from its parent company.

Systrom and Krieger left Instagram at a time when Facebook's future is more important than ever. Faced with the daily decline in the number of young Facebook users, the company will turn more and more to Instagram to build a future.

In a farewell message, Systrom virtually promised to create another company. He told Goode that he and Krieger would probably work together again, but that he had no time to start a new venture. He said that he wanted to spend the next few months becoming a good father for his nine-month-old daughter and exploring his creativity and other hobbies. (He recently took the plane.)

Systrom said it was confident that Instagram would continue to be successful even without its co-founders at the helm. "I want this thing to succeed," said Systrom. "If this thing tripled and became the most important thing in the world, it would be an incredible result for me, even if I do not make it work."

It remains to be seen why the co-founders resigned when they did. Systrom dodged a question from Goode about the sensation of telling Facebook CEO Mark Zuckerberg that he was leaving, except to say that he had a mix of emotions. But as a sign of a sudden decision, he declared that he had written this farewell message "very, very quickly".