If anyone's at fault here, it's me, but it's at least gratifying to me that Maurizio is better aware of how much his presence here is valued. I don't know what specifically provoked or precipitated his initial decision to leave; I do know that sometimes we can alienate others unnecessarily. We can cross lines that needn't be crossed, even after allowing for a sensible range of expression. Even if these threads and others like it have their excesses, I think they potentially afford us a "teachable moment," if you'll pardon the phrase. They help us recognize the underlying personal affection sometimes belied by our rhetoric -- and, maybe, just maybe, reexamine the bounds within which passionate, spirited debate can remain healthy.