We had a banterish atmosphere (lots of smack talk across the cubicle walls) with almost everyone on the team over 40. But it was grown-up banter, not high school banter. It wasn't passive aggressive, "hah hah only serious"; it was just fun banter. If we really wanted to communicate something to someone, it was handled very differently.

And when a woman joined the team, well, there wasn't any sexual harassment or sexism. But don't turn your back on her when she's got a nerf gun...