In a group meeting or one-on-one, it's a very bad look if you judge a person rather than what the person did. There's a huge difference and it your own credibility is at stake.
Judge the action, not the person
Suppose Jack Jones has just made a mistake that costs the firm $10,000. His CEO could say, "You're stupid." Or he could say, "That was a serious mistake." Clearly there's a difference for Jack Jones and his self-esteem, but it's not the point I'm making here. The point is that the first way makes the CEO look bad.
Why? Because we all have a subconscious desire for our leaders to have 'fundamental respect' for their followers. For all their followers. Fundamental respect is the respect you have for other humans regardless of what they do. A leader with executive presence can even fire someone for what they have done, and still have fundamental respect for what they are. Judge the action, not the person.
Strong leadership and fundamental respect
But - you might object - surely a strong leader tells it like it is. If Jack Jones did stupid, he is stupid.
No, that's a myth from the dysfunctional school of kick-ass leadership. And it only takes a moment of thought to see it: how many brilliant achievers have reached their status without flaws or mistakes? None, of course - good judgement comes from experience which comes from bad judgement. If you pronounce judgement on what a person is, you're saying he or she cannot improve. Be in no doubt, judging person rather than action will harm you more than your target. It's weakness disguised as strength.
I once saw a supposedly strong CEO (also a confident speaker) talking to 100 staff. An office junior asked a question most people thought was stupid. The CEO promptly belittled the person, with such wit that many laughed - and the CEO was clearly pleased with himself. What he missed was a subtle shift in the expressions of the audience, a shift which said: Poor guy. I'd better be careful. If I ask a question, the CEO could also treat me like that.
And here's what's really interesting: that subtle expression was also on the faces of those who laughed.
Incidentally, the same principle applies to positive feedback. Think carefully before you praise the person rather than the action. Think carefully before you praise what a child is, rather than what he or she has done. But that's another story.