There is nothing worse then "sabelotodo" guy stoping whole ronda because he needs to explain to some poor girl that this figure needs to be performed this way, and nothing else.
Those guys are total wankers . . . I wish they would dry up and blow away.
My girlfriend has studied and danced tango for over 10 years. Her coach – with whom she works weekly – is one of the people who introduced tango in my city, and has been studying and dancing tango for well over 30 years, and teaching it for well over 20. As a result, my girlfriend has good technique, to the extent that at a workshop a while back, Claudia Codega told her, "You have good technique." Our coach claims that if she wanted to teach tango, she probably could.
Anyway, this past weekend, my girlfriend and I went to a milonga together. She's my main dance partner, so we do that a lot.

And some guy there – who has been dancing tango for all of 2-3 years, and who is 100% self-taught and proud of it – invited her to dance. This guy is a brusque dancer who uses his arms, stares at his feet, regularly puts his partner outside his frame, and clamps his partner tightly when not doing that. My girlfriend accepted because the event was lightly attended and I had a tanda with a friend.
And this guy proceeded to stop dancing every few measures to critique my girlfriend's technique. Not just any technique, but technique in two particular areas where she has worked extra-hard to be clean and good – the technique that Claudia liked, in fact.
I was just floored that this foot-gazing, arm-leading, weirdly contorted leader did that. I didn't have words with him, because at a lightly attended event, that would've been unfair to the organizers. But I have been passing word of his bad behavior to followers, and my girlfriend has been doing the same.
People like that kill tango every time they step onto the pista.