I'm 35 and my wife is 30. I was born in 1980 which means some people would say gen-x and some would say millenial. I'm also the younger child, with my older sister being squarely in gen x.
My wife definitely has more of the typical millenial characteristics then I, and talking of our high-school experiences it almost seems like we were decades apart rather than just 5 years, though perhaps some of that is that we grew up on opposite coasts.
It helps to keep in mind these groups are just constructs to help sociologists talk about large groups of people. While they're good for talking about differences in generations, no single person is going to fit into any generational group perfectly. On top of that, it doesn't help that news outlets like to oversimplify these things for juicy headlines.
You're right. It's just one categorization of many. I might have more in common with a person who grew up in the same socioeconomic situation as me, but is separated by 30 years, then with someone born the same year as me with a vastly different socioeconomic background.
My wife definitely has more of the typical millenial characteristics then I, and talking of our high-school experiences it almost seems like we were decades apart rather than just 5 years, though perhaps some of that is that we grew up on opposite coasts.