The Google search-engine reveals several examples of people expressing this opinion; but I can find no trace that Alfred Hitchcock ever did, and I'm not sure he would have done. In fact, it sounds more like something Howard Hawks might have said about the Big Sleep, a notoriously confusing movie, but again there's no record. In fact, some people express the opposing idea - ie that confusion, rather than distracting from boredom, actually leads to it - so you may wish to be careful about using the idea in your essay.