I love it that adaptability is included among the middot. If it weren't, we might be tempted to think of mussar as simply a set of rules, and rigid adherence as the way to virtue. We might think of mussar as saying to us, "Just stay within the lines I set and you'll be safe." But, of course, real life provides too many exceptions, dilemmas, and puzzlements to allow for such an approach.
We need to follow the rules, but that alone doesn't produce virtue, which is the goal of mussar. To arrive at virtue we'll have to adapt, to grow, to change. It occurs to me during this month of Elul (which is traditionally a time of spiritual preparation leading up to the High Holy Days) that teshuvah or repentance is the height of adaptability. It means not just adapting to this or that circumstance, but rending our hearts, not our garments, and returning to the Lord (Joel 2:13).
I'm at a point in life, though, in which radical change looks difficult. The pathways are worn deep and it's hard to break out. But the prophets that we read during this season remind us that adaptability – even in its most radical form, teshuvah – is a gift, like all the middot. Hashem says "Return to me and I'll return to you" (Zech. 1:3, Mal. 3:7) and in response we can say "Turn us back to you and we shall return" (Lam. 5:21). This is why our tradition teaches that Elul, the month of teshuvah, is also a month of favor.