Most human beings cling to comfort, though science has proven that when you step outside of your comfort zone, that is where your most significant achievements take place.
If it weren't for taking uncertain steps out into a scary world, we would still be living in caves and throwing rocks at dinosaurs, waiting around for someone to discover fire.
Thomas Alva Edison would never have given us the light bulb, and we probably wouldn't know that bacon goes great with everything.
Most people just stay right where they are, because they are frightened by the possibility of failure.
Since they have their family to provide for, they make the justification that they shouldn't tempt fate, since moving to a new career might not turn out so well. So that person sticks with their current career even though they are not happy, years later wondering "what could have been."
Sports records fall every day because athletes keep pushing themselves. They are not happy with their current level of achievement.
The result of becoming uncomfortable, training as they have never trained before, is new personal bests and sometimes world records.
This is because of something known as the Yerkes-Dodson Law.
Stress leads to achievement?
Dodson and Yerkes were a couple of psychologists who, in the earliest years of the 20th century, discovered that stress leads to achievement. What they found was that significant achievement did not happen until a person took small steps outside of the environment, surroundings, and behaviors where he felt most comfortable.
They noted that when someone was put in an entirely uncomfortable, stressful environment, performance was horrible. However, when you take small steps outside of your comfort zone you slowly began to expand the area where you are happy and comfortable.
Over time, it becomes easier and easier to take on new tasks and expose yourself to unfamiliar experiences.
If your job is killing you, physically or mentally, maybe you should switch careers.
Don't take a giant leap, take a baby step instead.
Rather than immediately moving from one career to another, why not take a part-time job in a career that interests you?
Maybe you can sign up for classes or certification in some field that has captured your attention.
These small steps outside of your comfort zone will eventually give you the confidence to move onto an entirely different career if your current field of employment is not working out.