On Thursday, Facebook CEO Mark Zuckerberg invited the public to a "town hall" style question-and-answer session that he has held with Facebook employees for the last eight years.

The iconic billionaire CEO fielded the most popular questions that were submitted via a Facebook event page set up a week before the online event, which was streamed live over the same page. Zuckerberg, who had with him a few of Facebook's top executives, shared his thoughts on everything from features such as the standalone Messenger app and the lack of reach by Facebook pages to his feelings about the movie "The Social Network" and why he wears the same plain grey t-shirt every day.

Most pressing among the featured questions is why Facebook decided to separate Messenger from the main Facebook app for mobile, to which Zuckerberg admits it is a "big ask" to have users install another app to send messages. However, he says messaging is one of the few things that people do more than social networking, and separating the two functionalities makes it easier for people who want a simpler experience.

"On mobile, each app can only focus on doing one thing well, we think. The primary purpose of the Facebook app is News Feed," Zuckerberg says. "Messenger is faster and more focused. If you're using it, you respond to messages faster, we've found."

Also addressed was the wide-ranging complaint by many businesses who say less and less people are seeing their posts, to which Zuckerberg confirms that only 10 percent of all friends' posts are seen by a user on his curated News Feed. Zuckerberg says he wants Facebook to become "the perfect personalized newspaper for every person in the world."

And that is also why Zuckerberg doesn't care about Facebook losing its "cool" factor. More than being the "cool" thing to do, Facebook is supposed to be something like water or electricity; "it just needs to work."

"My goal was never really to make Facebook cool. I am not a cool person. And I've never really tried to be cool," he says. "You go home, you turn on the lights, right? You're probably not like, 'Yeah, electricity!' It just needs to work. My goal is that the ability to connect and communicate should be that. It just should work."

Zuckerberg also mentions one of the features that never saw the light of day, specifically a News Feed with lots of space and big images. He says: "We kind of ate our pride," after holding a press event heralding the release of the new design and finding out that beta testers had less engagement on the new News Feed.

"At Facebook, we have these big monitors," Zuckerberg explains. "It gave us a blind spot to the computers most people are using in the world."

Also interesting was the fact that the Facebook CEO found his portrayal in Aaron Sorkin's Oscar-winning "The Social Network" to be "hurtful." The film, which focused on Facebook's early days in Zuckerberg's Harvard dorm room, suggests that one of the reasons he founded Facebook was to attract women after being dumped by his then girlfriend for being a jerk. Zuckerberg says he was already dating Priscilla Chan, his wife, when he started Facebook. In the past, the CEO would joke about how the film at least got his wardrobe right.

Speaking of wardrobe, Zuckerberg says he has more than one grey t-shirt. COO Sheryl Sandberg steps in to say one of the biggest things she has contributed to Facebook was "I went around telling people Mark actually has more than one of that t-shirt, which people found to be reassuring."

There's a reason for that. The boy-genius entrepreneur of the century says spending time deciding what to wear or what to eat for breakfast is a waste of time and energy.

"I really want to clear my life to make it so I have to make as few decisions as possible about anything except how to best serve this community," he says. "I feel like I'm not doing my job if I spend any of my energy on things that are silly or frivolous about my life."

Zuckerberg points out he's got company, and says Steve Jobs had the same reason for wearing his signature black turtleneck all the time and President Obama for having someone else choose his wardrobe for him.

However, while the Facebook CEO is open about many of the questions thrown his way, there were also some questions that didn't make the cut. One question by Jenn Tonak about a Facebook site for kids, where privacy and security are presumably central features, is left unanswered. He also ignores a question by Samir Mezrahi about Facebook acquisitions that did not work out. Also unanswered is Shawn Micheals' question about when Facebook will introduce a Dislike button, probably because former CTO Bret Taylor already answered that one. Taylor, who created the Like button, says a Dislike button would invite too much negativity and could become a trigger for cyberbullying, for which Facebook is already criticized.

Alas, Zuckerberg also does not answer one of the most important questions posted by Kasey Fanton: "What beer were you drinking when you created Facebook?"

A video of Zuckerberg's Q&A session is posted on the event's Facebook page.