regarding the whole co-worker thing - I also think that a part of it depends on your relationship with a particular co-worker.

One woman here became a grandmother again a few months ago. She has a picture of the little guy as her wallpaper on her computer. Because I genuinely like this person, it was really easy for me to gush over her grandson.

But by the same token, she didn't force the picture on anyone, so that makes a difference too.