Do you ever feel like not waking up on a Monday? Do you dread the morning commute because you know the work day ahead is going to be nothing but headaches? How do you overcome this? One answer may be mental strength.

Mental strength significantly affects your self-discipline. In fact, there's a strong correlation between having a high level of self-discipline and being mentally strong. 

Some studies even show that self-discipline is an essential attribute of people who earn more money since discipline is an underlying factor in achieving personal goals. Simply put, people who earn more often have high levels of self-discipline and the mental toughness to finish whatever they started and see it through to the end.