A friend of mine e-mailed me a little while ago to talk about the curious phenomenon whereby people suddenly decide they need to pick others' battles for them, without any outside prompting, much less encouragement from the supposedly "aggrieved" themselves.
The examples cited were from back in high school (remember, we just had our tenth reunion, so there was cause to reminisce) but you can imagine how it could happen anywhere -- someone thinks they see another person being teased, picked on, taken advantage of, etc. and gets charged with the righteous indignation to carry that person's flag into battle, yell and scream, make a big deal, etc. without ever asking the supposed *victim* for his or her input or feelings in the first place.
Definitely sounds like a good recipe for trouble-making, and I think you could justifiably cast aspersions on the fire-and-brimstone thrower's motivations in these types of cases.
What may seem even less obvious, though, is when this is done in reverse -- when someone decides to play the role of the Unsolicited Peacemaker.
I think you know where I'm going with this, but just to flesh it out, here's how it usually works. You know I don't really like or get along with John Doe. You know that John Doe generally feels the same way, but we sort of mutually coexist on some plane of generally unfriendly equilibrium. So, you take it upon yourself to continually poke and prod to either myself, Mr. Doe, or both of us about the situation. You may do this under the guise of wanting to be the next Ralph Bunche or Ban Ki-Moon, but I would posit, your action makes you anything but.
Unless there's a simple disagreement that you can see and understand from your third-party vantage point (and thereby solve to save the day and make everyone happy), the truly best thing you can do in these situations (or the original ones described above) is to live and let live. Follow the playground wisdom of "mind your own business" and just understand that not everyone is going to get along. When you continually remind people of it (i.e. by saying, "Well, I was going to call Sally to come out with us, but I didn't because I knew you were coming"), you're poking a stick into a hornet's nest that no one ever asked you to disturb. Yes, you may not like said person, but no one should assume you're so childish that you can't bear the thought of sitting at the same 11-person table together.
There's also a whole other angle worth mentioning here -- to vent is human. Because I trust you, I may tell you something about John Doe today that doesn't even necessarily reflect the way I *really* feel about him. If you understand that, great, but if you don't, you can certainly use that down the line to foment discord, which represents one of the lowest forms of human behavior.
Again, this may be self-evident, but if it's not, here goes -- we're all inevitably going to get upset / feel misunderstood by our bosses, co-workers, friends, spouses, neighbors, etc. It's also inevitable that when those feelings start to boil over a bit, we're going to tell someone. Any judicious listener should recognize that for what it is, and know that it's not a repudiaton of someone's entire character or being, but a much simpler, natural way of letting off steam -- a good old-fashioned vent.
For instance, I have a neighbor who has been known to make the occasional bizarre comment to me -- most recently, some analysis about my choice of elevator (our building has two), which struck me as equal parts funny/bizarre because it was clear that this person had spent a lot more time thinking about it than I had (which is to say, zero). What was an arbitrary decision for me (I park near one elevator and I live near the other, so it's really a toss-up), led to something I found to be truly weird and would quickly share with you over a laugh and a beer, but never expect it to go anywhere past that. Just because I think someone's a bit, well, kooky doesn't mean anything past that, and doesn't even cloud my overall opinion of the person, which happens to be very positive.
To wrap this entry up, I would say a decent measure of someone's character is the way he or she can process information that other people share and then handle it in a mature way that generally works towards the interest of all involved.
Many more times than not, that's going to mean NOT taking up some unsolicited cause and starting a fight under the guise of wanting to stand up for the Little Guy, and it'll mean NOT trying to gum up the works in other peoples' lives by "intervening" every time they express an innocent, in-the-moment vent or just honest-to-goodness dislike of someone else.
Hey, sometimes that happens.