Can William Trevor write anything bad? mediocre? even just ordinarily good?

Every single one of the stories in William Trevor's "Selected Stories" is a small masterpiece. Does he ever write anything bad? mediocre? just ordinarily good? He's taken a single tone of voice and a narrowly circumscribed geographical sphere - mostly rural or suburban Ireland, England sometimes - and found an astonishing abundance of material, people, conditions, and situations. Every story I find myself thinking: there's enough material here for a whole novel. Yet: the real accomplishment is that Trevor can encompass a whole novel within the scope of a short story. A novel would be superfluous. You'd think he would burn through his material at too rapid a rate: for most writers, stories are just vignettes or, increasingly, selections from a novel in progress, but for Trevor each is a unique and independent work of art, so how does he find such a wealth of material? I'm struck in particular by the somewhat long (30 pp.) story Lost Ground, about an Irish Protestant boy about 16 who has visions of an appearance of a woman who calls herself Saint Rosa, and the boy feels compelled to preach about his vision - he sees it as a call for tolerance and peace. He's also clearly mentally disturbed (though Trevor tells the story beautifully, so that we're uncertain initially whether Saint Rosa is a real person). Story is about the boy's relation with his fiercely militant father, his craven and accommodating brother-in-law (a minister), the divided community - an incredibly difficult scene when he visits the Catholic priest and is rebuffed, and a powerful showdown with his father - and the story leads inevitably toward a tragic end, told unflinchingly, hard as flint. One masterpiece among many.