the ability to understand and share the feelings of another.
One of a designers best tools is empathy. You can practice with this tool everyday in hundreds of ways. On the sidewalk or on Twitter, in the corner bodega or in a restaurant. Before that knee-jerk reaction to point a finger and complain kicks in, try to understand.
Understand people's feelings and choices and actions. Understand why your favorite brand of whatever makes the choices they do. The more you practice empathy, the better your designs will become.