There're multiple reasons to hang out in Shirlington -- assuming that Gmaps is correct, and there really are two Johnny Rockets right across from each other. Oh? Ok. For an actually real second reason to head over there: Samuel Beckett's.
Named for the Dublin wordsmith (and lined with his quotes, like "...Try again, fail again, fail better"), Shirlington's Beckett's is a massive Celtic temple to all things pub-ly, sporting a huge bookcase covered with Emerald Isle artifacts, furniture/chandeliers imported from across the pond, and walls lined with old Irish black 'n white family photos, the former of which makes you feel better inside -- isn't it great to see the two O'Bannon brothers together!? The dark mahogany bar's more than stocked with Irish fuel, spewing 12 drafts including Smithwicks, Magner's, and Kilkenny, and boasting two shelves straining under a selection of 15+ Irish whiskeys, with top-billers like Red Breast Pure Pot Still, and Midleton Very Rare, which the soon-to-be princess's recent tabloid exposure has made factually inaccurate. The menu pulls heartily "From the Land and Sea", sham-rocking (oh!) "Braised Lamb Shank" in a red wine sauce with champ potatoes, "Two Way Fish Cakes" (one smoked, one not), and a smoked whitefish (in a creamy wine base) served en-croute and dubbed "Dingle Pie", as opposed to "Dangle Pie", which his shorts somehow manage to conceal.
For the traditionalist, they've also got a..."The Traditionalist" menu, including a full Irish breakfast and authentic bangers 'n mash -- also what you did to the keyboard upon learning that the Johnny R's at 2751 South Stafford Street was just one of Google's cruelest glitches.