If for example I had some idea, which as it turned out would be quite wrong, was going off of the tangent, Watson would tell me in no uncertain terms this was nonsense, and vice-versa. If he would have some idea I didn't like, and I would say so, this would shake his thinking about, and draw him back again. And in fact it is one of the requirements for collaborations of this sort, is you must be perfectly candid, one might almost say rude, to the person you're working with. It's useless working with somebody who is either much too junior than yourself or much too senior because then politeness creeps in. And this is the end of all real collaboration in science.