In a rare moment of openness and vulnerability, Hillary Clinton has opened up about why she thinks she comes across as "cold".

In a Humans of New York post, she talks about her experience of doing the law school admissions test at Harvard. She recounts how the men in her class began insulting her, as one of the only women in the room. Comments included: "You don’t need to be here," and "There’s plenty else you can do".

"It turned into a real 'pile on'." she says. "One of them even said: ‘If you take my spot, I’ll get drafted, and I’ll go to Vietnam, and I'll die.’"

This, Clinton says, it what turned her into the woman she is today. And it's a struggle so many women deal with: finding a balance between standing your ground, and still being "warm" and "friendly"—two words rarely used to describe her.

"I know that I can be perceived as aloof or cold or unemotional. But I had to learn as a young woman to control my emotions," she continues in the post. "And that’s a hard path to walk. Because you need to protect yourself, you need to keep steady, but at the same time you don’t want to seem ‘walled off'."

Clinton was criticized for not smiling enough at the Commander-in-Chief Forum on Wednesday night. Republican National Committee Chairman Reince Priebus tweeted that the former secretary of state "was angry [and] defensive the entire time—no smile and uncomfortable."

This is how she responded:

Actually, that’s just what taking the office of President seriously looks like. https://t.co/Pyn92mesom

— Hillary Clinton (@HillaryClinton)

Before adding, “I don’t take anything seriously that comes from the RNC."

Snap.

It's one of the far-right's favorite insults of the Democratic presidential nominee: that she's hard-hearted and soulless. So much so that when her daughter, Chelsea, gave birth to her first child, Clinton had to use that event to "humanize" herself. To make herself more relatable in the public eye.

But as she points out in this HONY post, it's a survival tactic. And one so many of us both employ and are criticized for.

"If I create that perception, then I take responsibility. I don’t view myself as cold or unemotional. And neither do my friends. And neither does my family. But if that sometimes is the perception I create, then I can’t blame people for thinking that.”

It's no secret that women face a double standard when it comes to "putting on a happy face".

And Clinton smacked down the whole argument that she's completely "walled off" by sharing such personal insights into her character.

Read the full Humans of New York post below: