If you ask pop culture, the Irish are known for loving three things: fightin', bonin' and drinkin'. The lads and lasses of the Emerald Isle rarely even put up a fight when thusly characterized, lest we find them pugnacious*. To illustrate those points: we call a broken bottle an Irish Switchblade, siblings born in the same year are Irish Twins and a vicious hangover is the Irish Flu. The good, fair people of Erin have one more namesake: the Irish Goodbye (henceforth to be called the IGB). An IGB involves leaving a gathering, perhaps at a pub, bar or boozing hole, without so much as a "good day, boyo" to your compatriots.
The IGB is also a powerful relationship technique too. The move goes like this: Person A is sick of dating Person B, perhaps through no real fault of Person B's (as most people would agree Person B is pretty alright). Person A decides to save a headache and an explanation by just picking up stakes and making a beeline for greener grasses. Person B is a little confused by the sudden lack of contact given that Person B committed no faux pas and thought Person A had a reasonably good time to-date. Person B attempts contact with some innocuous inquiry and waits to hear back (cue spinning clock jump cut). Person B, not trusting modern technology, tries again one to three times. Person A does not stray from the plan. Person B eventually is struck by a rogue beam of golden sunshine, mentally hears some iteration of Liz Tuccillo and Greg Behrendt's catchphrase (... just not that into you), nods once and continues life. Easy peasy George and Weezie. Read: Is It OK To Break Up Via Email? We Say Yes.
Frankly, the IGB saves an awkward conversation, an even more awkward face-to-face meeting or a most awkward "Dear Person B" letter. Everyone's a winner because no one has to hear or say, "it's not you, it's me," "I'm just terribly busy right now" or "for some reason, I just want to punch your face in." Unfortunately, it's not always that Simple Jack. Some people can't take a hint (though it should be noted that it takes way more energy to call, text or send a letter than it does to ignore all of them). Sometimes Persons A and B may bump into each other inadvertently and have a painful moment of recognition. But sometimes, the IGB is wickedly misused.
The IGB is a perfectly good way to give a relationship the Heisman if no downtown fluids have been exchanged, no items of value, sentimental or otherwise, have been left at Person A's domicile by Person B** or the relationship has gotten serious. Obviously, it's easy to judge when you've gotten it on (though the definitions "it" and "on" vary by Zip Code) or possess something important to the other party (like your heart). Nailing down when that friendship went from casual to formal is a tricky one.