On Pedagogical Tools: Is swearing or chewing someone out a viable method?
It's one thing to criticize the group for poor work - I've witnessed this and it is fully called for to say that the group has come unprepared and has underperformed. It's a very different thing for a professor of all people to lose their cool and use expletives in front of students. I am in Europe and this is poor personal control, poor personal culture, and by all means unacceptable behavior within a classroom. No matter how bad a group - they will deservedly get a bad grade in the end - but you can simply never - and it is never acceptable to lose your cool like that and pretty much insult students  in front of their peers. In school we get grades, not expletives. This is never acceptable. Never.