Tim Cook Knocks Android in George Washington University Graduation Speech

Apple CEO has a bold message for Android users.

"Before I begin today, they've asked me to make a standard announcement ... about silencing your phones," Cook told graduates.

Aside from his Android jab, Cook used the opportunity to challenge graduates to make a difference in the world.

"At Apple, we believe the work should be more than just improving your own self. It is about improving the lives of others as well," Cook said.

"I took the job and changed my life," he said. "It has been 17 years and I have never once looked back."

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