Squid: One of the most important factors in what we hear is the shape of our outer ears (and, no surprise, everyone is different). Your experiments are, in effect, altering that shape. You are not suddenly "hearing more from your system." You are hearing through different ears. In some cases, as when you cup your hands behind your ears, you are hearing less--specifically, you are blocking reflections from behind (and possibly beside) you. It may appear that you're hearing more detail because you are increasing the ratio of direct to reflected sound you hear.
Now, what have you learned? You've learned that reflections are VERY important. In fact, they are much more important than most of the components in your system. So keep working on that, and recognize that room changes are going to be much more subtle than your earflaps. Work on all the first reflection points--floor, walls, even ceiling. (You said you had a lowish ceiling. That's a factor.)
Also, keep in mind that reflections are normal, and even good. If you sit in the middle of Carnegie Hall with your eyes closed, it can be hard to tell where the music is coming from.
Now, what have you learned? You've learned that reflections are VERY important. In fact, they are much more important than most of the components in your system. So keep working on that, and recognize that room changes are going to be much more subtle than your earflaps. Work on all the first reflection points--floor, walls, even ceiling. (You said you had a lowish ceiling. That's a factor.)
Also, keep in mind that reflections are normal, and even good. If you sit in the middle of Carnegie Hall with your eyes closed, it can be hard to tell where the music is coming from.