Ever held your tongue in a meeting? Being afraid to speak up can be costly, says this Microsoft exec

You may sometimes be hesitant to speak your mind at work. But when you don't share your thoughts, you miss the chance to be genuine, said Ahmed Mazhari, the president of Microsoft Asia.

"Being genuine is being clear, and when you're clear, you have to share what you feel," he told CNBC's My Biggest Lessons.

Mazhari said managers, too, have a role to play in fostering open communication. As much as he encourages employees to speak up, this can only happen if bosses create an environment where people feel comfortable voicing their opinions.

"Sometimes, great ideas would never surface because one does not have the courage to speak, or one does not create the environment to speak," he said.

Watch the full video for Mazhari's biggest lessons.