When you sleep, your brain literally recharges, removing toxic proteins that accumulate during the day as byproducts of normal neuronal activity. 

This ensures that you wake up alert and clear-headed. Your energy, attention and memory are all reduced when you don't get enough quality sleep. 

Sleep deprivation also raises stress hormone levels on its own, even without a stressor present. 

Happy people make sleep a priority, because it makes them feel great.

You can't reach your full potential until you learn to live your life in the present. 

It's impossible to be happy if you're constantly somewhere else, unable to fully embrace the reality (good or bad) of this very moment. 

To help yourself live in the moment, you must do two things: First, accept your past. If you don't make peace with your past, it will never leave you. Second, accept the uncertainty of the future. Worry has no place in the here and now.

Most of us have no problem marveling at our friends' good qualities, but it can be hard to appreciate our own. 

Learn to accept who you are, and appreciate your strengths. Studies have shown that practicing self-compassion increases the number of healthy choices you make, improves mental health and decreases your tendency to procrastinate.

Taking time to contemplate what you're grateful for isn't merely the "right" thing to do. It also improves your mood, because it reduces the stress hormone cortisol by 23 percent. 

Research conducted at the University of California, Davis found that people who worked daily to cultivate an attitude of gratitude experienced improved mood, energy and physical well-being. 

It's likely that lower levels of cortisol played a major role in this.

Getting your body moving for as little as 10 minutes releases GABA, a neurotransmitter that makes your brain feel soothed and keeps you in control of your impulses. Happy people schedule regular exercise and follow through on it because they know it pays huge dividends for their mood.

Happy people live by the motto "Fool me once, shame on you; fool me twice, shame on me." They forgive in order to prevent a grudge, but they never forget. 

The negative emotions that come with holding onto a grudge are actually a stress response. Holding on to that stress can have devastating consequences for your health and mood.

Happy people will not be bogged down by mistreatment from others, so they quickly let things go and are assertive in protecting themselves from future harm.

Attempting to repress your emotions doesn't just feel bad; it's bad for you. Learning to be open about your feelings decreases stress levels and improves your mood. 

One study even suggested that there was a relationship between how long you live and your ability to express your emotions. 

It found that people who lived to be at least 100 were significantly more emotionally expressive than the average person.

Rather than dwelling on the things you can't control, try putting your effort into the things that you can. 

Have a long commute to work? Try listening to audiobooks. Hurt your leg jogging? Try swimming. More often than not, we take the bad and let it hold us back when it doesn't have to. 

Happy people are happy because they take their failures in stride, not because they don't fail.

People's core attitudes fall into one of two categories: a fixed mindset or a growth mindset. 

With a fixed mindset, you believe you are who you are and you cannot change. This creates problems when you're challenged, because anything that appears to be more than you can handle is bound to make you feel hopeless and overwhelmed. 

People with a growth mindset believe that they can improve with effort. They also outperform those with a fixed mindset because they embrace challenges, treating them as opportunities to learn something new.