Widowed at just 26 years of age, Amy Morin knows a few things about hardship and the struggle to remain mentally strong in the face of adversity.

Despite the tragedy she suffered, Morin has gone on to become a psychotherapist, columnist, and author. Her most recent book is 13 Things Mentally Strong People Don’t Do.

I discovered Morin’s book (which I’ve not yet finished) after a friend shared with me her 2015 Ted Talk, and I was immediately drawn to her intelligence, positivity, strength and humor.

There is also something refreshing in her philosophy, which rejects the idea that humans are merely or primarily products of biology and external social constructs. Morin clearly believes that mental strength, like anything else, is a virtue that can be learned.

Here are three things mentally weak people tend to do, according to Morin:

1. They Feel Sorry for Themselves

People get bummed out. They get sad. They get lonely. They get angry. These are very human emotions each of us will repeatedly experience in life.

Self-pity is different. Thoughts like “Why does this always happen to me?” cause one to get stuck and remain focused on the problem, Morin says.

Instead of finding solutions to problems, people who lack mental strength often find themselves “hosting their own pity parties.”

2. They Give Their Power to Others

People often forget that they are the ones in control. As Morin points out, one does not have to do anything. Are there consequences for not doing certain things? Of course. But you don’t have to go golfing with your father-in-law. You don't have to do your husband’s laundry. The truth is, every day we make choices, and our lives are largely based on those choices.

“As adults who live in a free country, there’s very few things in life you have to do,” Morin says. "So when you say you have to work late, you give away your power.”

This tendency is manifested in other ways, too. We blame others for holding us back—politicians, co-workers, friends, even family. Or we get angry that we cannot get someone to do what we want. We envy others because they have something we desire. It is within our power to control these actions and emotions.

Mentally strong people understand this often forgotten truth: You’re in control of yourself, mind and body.

3. They Think the World Owes Them Something

Many people, Morin says, seem to believe that they deserve success. Why? Because they work hard. But believe it or not, it is not written that if one work’s hard one will become successful.

“Expecting success to fall into your lap like some kind of cosmic reward will only lead to disappointment,” Morin says.

Mentally strong people tend to understand that life is not fair—Morin’s story makes this abundantly clear—and the world owes us absolutely nothing (a fact many of us are reminded of on a daily basis).

So What's the Secret to Mental Strength?

Purging these bad mental habits from our mind is the key to becoming mentally strong, Morin contends. Like physical strength, it comes through training. This requires dealing with one’s emotions and being honest with ourselves.

Sounds easy, right? Sadly, no. As T.S. Eliot once wrote, “Humankind cannot bear very much reality.”

Eliot’s quote made me wonder something. Is the sign of a mentally strong person one who can face reality and be honest with his or her emotions?