Soft skills are the interpersonal or “people” skills that help you to successfully interact with others in the workplace. Regardless of the job, you have to have the ability to interact effectively with supervisors and people in both verbal and written format.

Today individuals are measure on both their “Hard Skills” sets (technical, manual skills) and "Soft Skills" sets. If you have a negative attitude, can't get along with others, don’t have verbal and written communications skills, don't work well as part of a team, and aren't able to think creatively and critically, it will be difficult to increas your earning potential. 

It may not matter how well educated and competent you are. You need to have some soft skills to get the work done.