A colleague sent out an announcement about good news to a whole slew of email lists including departmental lists, college lists, etc. There are a LOT of people on the lists.
I hit reply and congratulated the colleague, and wished well. I'm sure some other folks did that.
But yes, a surprising number of people hit reply all, so that we can all read their messages of congratulations. Really.
And of course, were I to send something out suggesting that perhaps reply all is not necessary, I would be the worst and meanest, nastiest, most despicable person ever.
But people, most stuff broadcast widely does not require a reply all to share your congratulations.