> The hard part for me is to identify which parts of my personality are jerk-like, and which parts—when channeled appropriately—are useful (a team lacking critical voices is also going to be ineffective).
I think this might be the wrong way to think about this stuff.
Different communication strategies appeal to different listeners. Rather than analyzing yourself, saying "some parts of me are effective, others fail," I think it's more useful to analyze your interactions. You've almost certainly had really productive, energizing debates with people in which everyone walked away feeling glad that all the cards were laid on the table.
You've probably also had really unproductive, demotivating debates in which people felt attacked, unable to express themselves, and frustrated.
Here's the skill to work on: before you start that debate, try to understand the person you're talking with. How do they want to talk about this topic? Do they do better with collaborative, friendly, "That's a good idea"-type discussion, or with hard-edged debate? Now, mold your communication to their style.
You said this yourself in your #2, but I want to triple-underline it. That's the whole job when you are communicating. It's all about finding ways to get your point across as effectively as possible, which means it's your job to communicate the way they will listen to.
This is hard! But it's worth it. You definitely don't want to just have one way of communicating - that just makes you frustrated when people aren't receptive to that style.