Most transgendered people i know are basket cases?

I have nothing against transgendered people, or their right to be transgendered. But I'm suspicious about whether a lot of people who claim to be transgendered really are.

The first transgendered person I met seemed mentally normal; I have no trouble believing that he's felt this way his entire life, and I have no problem with him getting a sex-change or identifying as male. More power to him, honestly.

But a few years down the road, two friends of mine wound up declaring themselevs "transgendered," and in both cases it didn't add up, and they both had mental problems before.

The first one, "Susan," was a friend from high school. Throughout high school it was clear something was wrong with her; she believed she was possessed by demons, and had "memories" of a dog-headed demon casting a spell on her as a child. The "demonic posession" she described sounded a hell of a lot like the symptoms of Dissociative Identity Disorder. (Memory blackouts, journal entries she didn't remember writing, etc.) She also had a huge ego; she believed she had a special "destiny," was convinced she would grow up to be a world-famous artist (she gave me a picture once and said "keep this, it'll be worth something someday"), and she told everyone her "secret" (the demon thing). For the record, she also seemed to be attracted to men (we both had a crush on the same boy at one point). After high school I thought she'd grow out of her demon-thing, but then Susan posted online about how angry she was with a friend who called her "crazy" when she revealed her "secret" to her. That was when I stopped following Susan on DeviantArt. A few years later I learned from a mutual friend that Susan was now "male" and had changed her name to (sigh) Damien.

The second person is "Jim." Jim was my first boyfriend from college. He seemed eager enough to make out with me, and we broke up because of his obsessive crush on his female "best friend." He had high-functioning Autism, and admitted to also having auditory hallucinations (which he refused to get help for, for fear that meds would slow his brain down). A year or so after our relationship ended, he flunked out of college (having previously been a straight-A student) because he was "destroyed emotionally" by his "best friend" not returning his "love." This guy also had a flair for the dramatic. When I was dating him, he claimed to have 12 near-death experiences under his belt; dressed like Van Helsing 24/7 in a trench coat, fedora, and all black clothes; and had recently undergone a "life-changing" conversion to Christianity. A few years after college, he underwent another "life-changing" revelation, announcing he was transgendered. He specifically said that making out with me had made him realize that he "wasn't psychologically male." Now he's lamenting about all the "bullshit" he's had to put up with being transgendered. Oh, and he claims he's had another near-death experience.

Then there's the transgendered girl on YouTube, who makes videos about her Dissociative Identity Disorder, where her "alters" talk about themselves. She/they have stated that "the body" used to male. Kind of suspicious, that a person with D.I.D. ends up getting a sex-change. I wonder if it was really her decision, or if one of the alters wanted it.

Finally, there's a transgendered person on a website I frequent; she's been a regular there for years (so have I). She was always notorious for her immaturity and irrational rages, and always had a very cutesy, girly avatar when posting on the forums. Now she's "male." However I'll admit I don't know her well; I honestly wouldn't even think anything of it, if not for the other people I mentioned.

Ironically, the one of these four who seems most likely to actually be trans (IMO) is the obnoxious girl; it could explain her rages and her overly-girly avatars (if she was in denial or something). But the other three seem to be people who either want attention, or crave a change in identity, or both.

Is this trend common in people who are transgendered? Is it common for people to seem completely heterosexual before announcing they are trans? Is it common for trans people to have such serious mental issues? Or am I just a magnet for weirdos?