Work is a social setting.
On the job, you must interact with co-workers in many ways, building relationships of trust and often interdependence. Your co-workers will think you are standoffish. You won't be able to rely on them when you need help with a project. Your participation on office teams, an increasingly important aspect of work, will be blocked. Employers consistently report that they are looking for job candidates who have good grades, who have experience, and who have been involved in student and professional organizations.