This keynote speech was given at the "Progress in Paper Physics Seminar", which was held in Montreal, Canada in 2010. This was Derek's last speech at an international paper physics conference. The organising committee asked him to send a message to young researchers in the paper physics community. The topic of his talk was "the weakest link in chain" which gives advice that is still timely for researchers that want to make a real difference in the forest products industry. This paper is based on his speaker notes which we were fortunate to find.