When does being a “do-gooder” go too far? If that happens, what’s behind it? Obsession? An overwhelming sense of altruism? What motivates them to risk the well-being of themselves and sometimes loved ones? What is it about them that makes the rest of us uncomfortable? These are the questions New Yorker writer Larrissa Macfarquhar explores in her book of essays “Strangers Drowning,” and they were the subject of her fascinating and animated talk for UCSB’s Arts & Lectures. Perhaps the most extreme example is of Sue Hoag & Hector Badeau who kept taking on adopted children until their “family” swelled to an out-of-control 22 kids. Very hard times ensued, but they muddled through and even with death of 3 of their children, there is a large brood of grandchildren and great-grandchildren who visit every year. So, are the “do-gooders” an inspiration, or are they just crazy? The answer is a personal matter, but Ms. MacFarquhar gives one a lot to think about when searching for it.