As a psychotherapist I’ve always had an interest in mental strength, but my interest in the subject became personal when I experienced a series of losses. In 2003, my mother passed away suddenly from a brain aneurysm. Then, on the third anniversary of her death, my 26-year-old husband died of a heart attack.

A few years later, my father-in-law was diagnosed with terminal cancer and I found myself thinking things like, “Why do I always have to lose everyone? This is isn’t fair.” But ultimately, I knew that way of thinking wasn’t going to be helpful.

I knew indulging in unhealthy habits, like self-pity, would only provide a temporary distraction from pain. So I sat down and wrote my list of the “13 Things Mentally Strong People Don’t Do” as a reminder to myself of all things I’d need to avoid if I wanted to face another loss with as much strength as I could muster.

I never imagined that my list would go viral, or that I’d have an opportunity to expand my article into a book. I’m grateful those things happened, but initially, that list was meant for me. And I was glad that I had that list because within a few weeks of writing it, my father-in-law passed away.

Here are 5 of the 13 things mentally strong people don’t do:

1. Waste time feeling sorry for themselves

While it’s healthy to feel sad sometimes, dwelling on our misfortune and underestimating our ability to cope with pain is destructive. Self-pity keeps us focused on our problems, and prevents us from taking steps to improve our lives. Gratitude is one of the most effective ways to ward off self-pity.

2. Give away their power

Blaming other people for the way we think, feel, or behave provides an easy way to shirk personal responsibility. But the truth is, no one has the power to make you mad. You’re in control of your emotions and how you respond to others. Similarly, your boss can’t make you work late. There may be consequences if you don’t work late, but it’s a choice. Take back your power by acknowledging your choices.

3. Fear taking calculated risks

Emotions often cloud our judgement. When we’re excited about an opportunity, we underestimate the risk. When we’re anxious however, we overestimate the danger. Balance emotions with logic so you can calculate which risks are worth taking, and move forward with confidence.

4. Resent other people’s success

Watching other people achieve their goals can stir up feelings of envy. But every minute you spend resenting other people’s success takes time away from working toward your goals. Write down your definition of success and focus on cooperating--rather than competing--with those around you.

5. Make the same mistakes over and over

Sometimes, we’re so focused on covering up our mistakes that we don’t learn from them. Rather than make excuses for what went wrong, acknowledge your blunder. Invest your energy into learning from mistakes so you can avoid repeating them.

Amy Morin is a psychotherapist, keynote speaker and the author of 13 Things Mentally Strong People Don’t Do, a best-selling book that is being translated into more than 20 languages.