Mitch: I wouldn’t say that it’s “maturing,” per se, obviously I’ve
done quite a bit of that as well, but my becoming more social than I used to be is just a change, not an instance
of maturation. There are loads of introverts who I would consider to be mature; in
fact, oftentimes being extroverted means having your immature side come out every now and then.
Which I’ll
admit can be pretty fun, but that’s not the point, the point is that it isn’t maturity.
I know exactly
what you mean about becoming sensitive; it’s so easy to make me feel guilty. Being disagreed with not so much,
but the other example that you gave, I’m the same way. There isn’t really anything you can
do about it, from my experience; what I’ve done is just acknowledged it, accepted
it, and realized that it really isn’t that much of a fault. Especially when it
comes to interacting with others, I call it “being too nice,” which I think is both slightly humorous
and also puts a positive spin on it.
I can’t say that I have any experience with PMS (as I hope is more
than apparent
), so I’m not even going to try to talk any about that, but I
will reassure you that there’s no reason to be “terrified” of us. I know I’m not, at any rate, and I
feel very confident in saying that it’s the same case with almost everybody else. 
Finally, "Mr.
Cellophane" is a character from the musical Chicago; his actual name is (I
believe) Amos, but his song that he sings is entitled “Mr. Cellophane.” The lyrics can be found
here.