A classic

(From CodeSOD: The Pyramid of Error)

if (error)
  if (fprintf(stderr,"An error occured while writing to the file")<0){
    if (fprintf(stderr,"An error occured while writing to stderr")<0){
      if (fprintf(stderr,"An error occured while writing to stderr")<0){
        if (fprintf(stderr,"An error occured while writing to stderr")<0){
          if (fprintf(stderr,"An error occured while writing to stderr")<0){
            return fprintf(stderr, "An error occured while writing to stderr");
            /* lets stop here, its enough */
          }
        }
      }
    }
  }