What's a pattern?

A pattern is something that is repeated ... and a pattern in the sense of A Pattern Language is a solution that is repeated.

One of the most difficult issues, is the quality of the pattern. It should be generative, as many people have pointed out. I think it's more useful to say it should be inspiring. That implies that it must be good. No one is turned on by a bad pattern: although in software the notion of an "anti-pattern" has taken root.

But that's just "do's & don'ts". The final quality of a pattern, is it's profundity.

A good pattern is something your head understands, and your heart knows is true. It ties together your feeling and your cognition.