When students drop by the office for help, whether during scheduled office hours or not, I've noticed that they almost never knock.
Our door swings shut, so it's not as though it's open and I'm expecting a courtesy knock. I just hear the handle turn and then there they are, walking right in. And usually they don't make much small talk first -- just launching right into "So I don't know what to do on #5 here..."
Everyone born before the Millennials always knocks, whether they're other grad students, tenured professors, or secretaries. We haven't had too many early Millennial grad students come by, so the lack of knocking may belong more to those born around 1992 and after. As bratty and socially awkward as the early ones are, the later ones are noticeably worse.
Where did they learn his habit? Or rather fail to learn the normal habit? They certainly didn't enter the teachers' lounge at school before college, and most of them have never worked, let alone barge into their manager's office. And they generally don't sleep over at each other's houses when young, or even hang out much in their "friend's" houses as teenagers.
So they must've picked this up at home, more or less the only place where they've ever had to interact with others socially, and certainly when it's in an environment where there might be closed doors. But why didn't they at least pick it up at home?
Do helicopter parents maintain an entirely open-door home environment? That would help them constantly monitor their kids, and allow the kids to come complaining no matter when. Floor plans are a lot more open these days than in the '80s, typified by the new "great room" in the McMansions of the past 20 years. Or do they have closed doors, but just give their socially clueless kids a pass whenever they interrupt someone else's activity unannounced, rather than prepare them for the real world?
Beats me. Whatever the cause, though, it's yet another telling sign of how unsocialized this generation is. Each of these things is small in itself, but piled all together, you understand why their co-workers have been complaining about how entitled the Millennials are in the workplace and at school.