Engine failures are the stuff of nightmares. Maybe not quite so agita-inducing as your mechanic calling with a compression report, but worrisome nonetheless, even if aircraft engines are designed with reliability in mind.
So are they reliable? Well, yes, if you let them be by slaking them with gas and oil, following the procedures written right down there in the POH and avoiding the maintenance blunders that cause a surprising number of engines to fail in flight.