The bipolar people I've dealt with have been incredibly sensitive to slights -- to the point of seeing them where there were none, or at least none intended -- while sometimes being oblivious about their own lack of tact. That's an obnoxious combination everyone finds off-putting.
There is, after all, no greater sin than hypocrisy.
On the other hand, bipolars can't help it. They have an organic condition that leaves them no choice but to perceive the world as they do.
If you weren't aware that someone was bipolar, and she lashed out at you for no apparent reason, you'd be less inclined to give her a pass. But if you were aware, even if you still felt a little wounded by her attack, you might at least be a little more understanding, even if still not quite fully accepting. And, you'd probably feel a little less wounded.
The fact is, most people who have been officially diagnosed, tend not to advertise the fact. ("Hi, my name is John, by the way, I'm bipolar, so if I act a little crazy you'll just have to excuse it.)
You can hardly blame them for this, since doing so would scare off potential friends -- or potential employers.
But telling people you've just met is different from telling friends. Once a friendship has been established, it might not be a bad idea for bipolars to own up to their condition; it would provide a handy -- and much needed -- excuse at times.
And, if your friends are actually friends, they can help you through these phases, sometimes simply by reminding you of them.
I've known people I'm pretty certain were bipolar, although none ever confided that fact to me. (I also think a few were never diagnosed.)
I once teased one such woman for the way she posed for a picture. I was later shocked to hear that she had cried about my teasing. Maybe I am an insensitive boor; but she had said harsher things to me. (She had been kidding, of course; but so had I.)
This woman was quite intelligent, and when in a good mood, very pleasant company: insightful, funny, and flattering. But you could tell almost immediately when she was in her Mr. Hyde phase: her face became taut, her body tense, and she would say things that made it seem she felt she had to reverse the compliments she had bestowed while in her Dr. Jekyll phase.
But, she had no choice about these moods. They just overcame her, and she was helpless while in their grip. And when I realized that, I had much more sympathy for her. (In fact, I later realized that the reason she hadn't accomplished as much as she might have -- despite being beautiful and smart -- was that she had been hamstrung by these moods her entire life.)
When you're in the depths of depression, the whole world is bathed in a negative light, and your emotions are fraught. That darkness colors every interaction you have with others.
Some might call a person who can dish it out but can't take it a "hypocrite." But if you call him bipolar, it more eloquently describes his behavior, and explains it as well -- while rendering less of a moral judgment. And, knowing that someone is bipolar predisposes you to make some allowances for his behavior, or, at least, to take it less personally.
The less of a deep, dark secret bipolar disorder is, the less shadow it will cast on relationships.