Amen to this. I really, really try to follow this, which is not too hard as I'm that way by nature. But, true story...

A few years ago I was at church, service ended, I'm in the grab a snack line. Beside me is a youngish woman I've know a long time. Her husband had worked at my worksite a few years before moving on. I hadn't seen either in quite some time. I broke my stay silent rule. "Hi, good to see ya. How's Tom?" I immediately knew I'd screwed up. She paused, flushed, said, "He's fine," then hurried off in tears. Her mother came up later and filled me in. Tom had done the classic run off with his secretary exactly that week. Left her and the two kids. Clearly it was a big step for her to return to church and try to move ahead without stupid people saying stupid things. I felt terrible.

Lesson learned for me: don't be rude and say nothing, but stop at "Nice to see you."