I think I first learned it from James Dobson, that our faults are usually our best qualities out of control. To be precise is a good thing, but being obsessive seldom is. To be warm-hearted is an admirable quality, but a chronic rescuer actually does harm. Viewing oneself in this way can be discouraging, as we see quickly we will never be able to eliminate the fault, because it is tied in with our deep character and our survival strategies. It is likely healthier to see the upside, though. Self-improvement comes not so much from going against the grain and attempting the impossible, but from ratcheting back on something we know to be valuable when it is under discipline.
I have been thinking of a young friend who has been beloved of all who know him. I wrote on a recommendation for him that "everyone is nicer when he is around." He has tended to be liberal for as long as I have known him, but it has taken a more intense turn these last few years. There have even been incidents where he wasn't...quite so nice. I don't see him much now, I may be assigning too much weight to isolated events. I did not have much to wonder about the cause. He was once in a minority of liberals among people who were either conservative or didn't care much about politics either way. For several years now he has been entirely among liberals. It occurred to me that the strength had shaded over into becoming a weakness. His ability to get along in live conversation is related to a tendency to take on the coloration of those around him.
We all do this, of course. Even folks like me who have a tendency to be the opposite, who try to balance a discussion by seeing value in the minority opinion, or seek for new angles on the conventional wisdom, still move in the direction of the people I am conversing with. I steer away from topics, or accentuate areas of agreement. I don't do well with people who are determined to blow through that and publicly insist on their point of view brashly.
I don't think I have ever applied this to groups. A group flaw may also be a strength out of control. I invite you to have fun with the idea, as it may be useful going forward.
I have come up to the edge of the idea, I think, in my frequently noting that liberals are generally more socially skilled and read the subtext of discourse very well. Two downsides occur to me. First, there has been a growing tendency for liberals to overread, to find sexism and racism in ever more dilute forms, until, like a homeopathic medicine, there is no longer any molecule left in the bucket. Secondly, it becomes to easy to spread ideas by social methods rather than logical or substantive ones. The people who "get it" are the people who get it, and a wink's as good as a nod. As Lewis noted in The Screwtape Letters, people laugh as if the joke has already been made. Conservatives have a different problem, in spreading ideas with sentimentality such as patriotic display - which is why they get so pissed when they perceive those symbols to have been slighted. All groups do some of both, of course. Liberals will often go to sad children displays, and conservatives will hold strongly to some social norms as important to telegraph early. Still, there is the overall tendency.
But I think there is more to this idea of group weaknesses being tied to strengths, and invite my excellent commenters to have a go at it. Have a care to look at your own groups as well.