Disillusionment of Ten O'Clock
Speaker? What speaker? We don't know who this guy is. Is he one of those folks in a white nightgown? Is he an old salt, sleeping in his boots? Or is he someone completely different, someone detached from the action, someone looking down on it all?
We think the speaker is probably closest to that last option, but honestly, we don't know much about the guy (or gal, for that matter). All we can really guess about this guy comes from what he chooses to tell us about these white nightgowned sleepers.
Because he laments the fact that none of these nightgowns are green or "purple with green rings" (4) and so forth, we can guess that this is a guy who likes a little color in his life. He would never, for example, paint the walls of his bedroom beige. No sir.
And we know from the fact that he seems to enjoy the sailors' dreams—of tigers in red weather—that this guy loves a little excitement, too.
Of course this leaves us with just one question: how do we get that color and excitement in our lives? Well, our speaker has the answer: by using our imagination. It's really that simple. See, the sailor doesn't have to go out to catch tigers in red weather. The dude can do it in his mind, because his imagination is a lot healthier than all those folks sleeping in boring garb.