It means do only what is needed. If you do anything extra, you could be wasting your effort and/or causing problems. Doing just what is needed is sometimes difficult for developers.
I have made the mistake of spending too much time slavishly implementing some pattern only to figure out later that it was just serving my need to implement the pattern, versus just getting the job done with a simple procedural script.
I have made the mistake of spending too much time slavishly implementing some pattern only to figure out later that it was just serving my need to implement the pattern, versus just getting the job done with a simple procedural script.