Developers need a variety of skills to succeed in their careers, and not just technical ones. Flexibility, ability to collaborate and learn fast, critical thinking, and leadership skills. All these factors increase the value of a developer as an employee and help them to grow professionally.
People who know how to deal with their emotions can achieve more in building strong relationships with others and gain better results in professional and personal life.
Barely anyone wants to work in a team with an aggressive colleague. Moreover, expressing emotions in a calm and positive way leads to an effective resolution of any conflicts, despite pressure or aggression on the other hand. A good emotional intelligence can not only empower communication, but also demonstrate maturity and leadership skills, which makes a person a stronger and more valuable professional.
Presentation skills are important for many professions, and software devs are not an exception. The ability to conduct meetings or explain the details of a project to a non-technical specialist is something critically useful. When it comes to coding, programmers are masters, but when it comes to presenting results, a lot have difficulties.
High level presentation skills increase the value of a specialist, helps in demonstration work results, sharing experience with colleagues or teaching others.
The ability to relax
It's pretty common for the developer to spend all the time behind the laptop. Especially now, when lots of people work from their homes. There is no separation between home and work, free time gets mixed up with professional tasks and the person is never able to fully relax.
Permanent feeling of tension cannot be good for mental and physical health. And here comes stress, insomnia and obviously decrease of productivity.
In order to avoid all these things, it is very important to be able to rest. Hobbies can be very helpful to distract and relax the brain (preferably not related to computer ones). Clear mind and healthy body will definitely make a good impact on professional success as well.