1. He's the only enlisted man in Starfleet. You ever see another one? Right, it's just him. Him and all those officers, from the traditional Ryker types to the very silly girl officers. Even aliens are officers, but not Miles. Is it because he's Irish? Women, Klingons, ditzy women like Janeway, Bajorans, even a Borg or two, Frenchmen... But not O'Brien.
2. He's the only married man in Starfleet. Now, that's probably an exaggeration, but it sure seems like it. Is that because he's Irish?
3. He's whipped. Keiko definitely wears the pantsu. And when Keiko temporarily turns into a ten-year-old, he won't get into bed with her. Definitely because he's Irish.
Jon Adams sees the humor in all this. I was made aware of this strip by Sparky Santos, and you can see more of this strip at Jon's site HERE.