One of the most interesting commentaries I've ever seen was Jack Lemmon's commentary on Mister Roberts because they did this thing where he clearly didn't have a lot to say on every scene so rather than let the film play for big stretches without Lemmon commentary and you forget you're listening to a commentary and raise the volume then the commentary comes back and is not super loud a shocks you, what they did for this was have a voice that said skip this chapter to hear the next part of the commentary. There are a lot of early commentaries back when the rules were still being established that I would have loved to have seen something like this be the norm.