I wish it were that simple. Most of us are good old fashioned American mutts, but a significant portion of the population picks only single ancestral heritages to latch onto. Like, I’ve got Irish ancestors, but I have so relatively few of them that to claim being Irish American would be misleading at best. We cosplay our favorite ethnicity once, maybe twice a year on the “appropriate” holidays, and maybe more if we’ve got cool clothing in our heritage like lederhosen and can play the concertina