One of the minor regrets, not really a big regret, is that I've never published a paper with Mac Burnet. I've published 500 papers, not a single one has Burnet as a co-author. He did not believe in putting his name on a paper if he hadn't done at least one third of the work himself. A sort of an honest unselfish approach, when it comes time to reap the glory you do it without having someone grabbing it instead of you.