Trigregalomaniac
A person subjectively accomplished in vapid, trivial, and/or inconsequential things, tasks, and/or skills. Considered to be a blessing and a curse, more so the latter. Pursuant to appraisal by significant others and/or commonplace passersby. Archaic and of Irish and Algonquian origin.
Sure, he always catches fish, but he's not really good at anything that matters. He's a Trigregalomaniac.