Our mightiest oak lost a huge chunk with no warning (in the middle of the night (in calm weather)), but utterly failed to kill our neighbors. Scraped a gutter, knocked some stuff off their walls. Luck +1.
Unwilling to let them live under a cloud of worry, we made the hard, painful decision to take the whole thing down. 160-180 years old, probably. Frowny face. R&R Tree Service did a fantastic job.