How do I get my girlfriend to knock off this annoying habit?

I met my girlfriend, Bethany, high school senior year, and we’re still together five years later. We’ve been living together since our Junior year in college.<br><br>She is a phenomenal girl, no complaints. She is the most attractive woman I’ve ever seen but she’s not a narcissist, she’s probably the nicest person I’ve ever met, she makes fantastic food, she’s* really good in bed, she takes care of herself, she’s a fantastic singer-songwriter, she’s about to graduate medical school, she’s well read and knowledgeable of the world and she’s genuinely interested in everything that I’ve got to say despite the fact that I’m just a janitor.<br><br>She’s got one habit though, that really gets me.<br><br>Sometimes, when she’s going about her day, she’ll say, in a perfect, Irish accent, “Thanks for lookin’ after me while I’m here.” <br><br>She’ll just say it out of the blue. I’ve heard her say it to her coworkers, to her professors, to fraternity brothers I’ve introduced her to, to people at the grocery store, even to me. She always looks incredibly serious when she says it too, which is weird because she usually has a smile on her face.<br><br>What can I say to her to get her to stop saying this? It’s not like I can just come out and say, “Knock off that annoying habit,” because she’ll think I’m calling her annoying, and I don’t want to give her that impression because honestly she is not.<br><br>Also, it’s important to note that Bethany is not Irish by blood or nationality. In fact, she’s German, and she can’t even speak Gaelic. It’s not like she’s just trying to connect with her heritage or anything. <br><br>What should I do here?