A number of the people commenting were observing that they saw elements of their own behaviour in the "unhelpable" types being described. I left replies with advice to some of these.
To a commenter who said they had brought everybody down without realizing it, I answered:
“without realizing it” is the trap there. Well... Now you have an opportunity to see things differently. Here's a piece of advice I have said many times to my friends:
When you start to notice your mistakes in retrospect, it can feel really terrible, but it's important to remember that seeing the problem AFTER it's happened is pretty much a prerequisite to seeing it WHILE it's happening, and eventually, with enough practice, seeing the problems your own behaviour could cause in the moments BEFORE you react to some stimulus.
When you realize your own role in your problems at ALL, it makes you stronger. It gives you the chance to do something about it. Even if you don't see the ways in which your actions may have been harmful until after you've left the situation, once you realize it, you unlock an opportunity to apologize, or look for ways to make it up to the people you have hurt, or even just to learn from your mistakes. You can't do any of that effectively without seeing the mistakes.
When you start being able to see it in the present, you will unlock the power to stop yourself, or call yourself on it. "Oh wait. I- I'm being a jerk aren't I. I didn't mean to do that, I wasn't seeing the situation clearly. I'm sorry. Let me take a moment to disconnect, walk, calm down, or otherwise gather my thoughts and try approaching it differently."
And when you start being able to see it coming in what you are about to say, you can change so quickly that other people won't even see the problems you decided not to cause.
Of course, that doesn't mean you won't face complicated situations where figuring out what the right thing to do is hard. n.n' But it will give you more options as you notice your own part, and practice acting in different ways, so you aren't always running on a terrible form of autopilot.
Good luck!