As the mother of a 15-year-old boy, I've heard "OK Boomer!" way more times than probably necessary.  I have to admit, the first time I heard it, I reacted negatively and loudly announced "I'm not a Boomer!"  (I'm close. But technically, no, I'm not a boomer.)  This reaction of course delighted my son and now it is his mantra every time he talks about something I don't understand or every time I talk about something he doesn't understand.