Sometimes I walk past women and give them a compliment, like saying 'Ma'am, love your hair and glasses,' but they completely don't notice me. I make an effort to project my voice and use a hand gesture, so it seems unlikely they didn't hear me. Unless they're wearing earbuds that I can't see, I find it puzzling. My question is, is it common for cold approaches to go unnoticed, even when making an effort to be clear and visible?