“Think outside the box” has become a mindless cliché these days. It’s repeated so often that the meaning has pretty much disappeared.
But it’s still excellent advice—if you know how to follow it. Unfortunately, most people are unaware they’re inside boxes, so they have no idea what it means to think outside of one.
Discussing somebody’s “box” can be like talking to a fish about water. The “box” is all there is.
Most of us are boxed in by beliefs that have been programed into our brains from day one by our culture, families, politics, and that 4th Grade teacher who told you if you kept reading comic books, you’d never amount to anything.