Why does the interviewee's posture so important in a job interview?

What does "must never have ever been or even" mean?

This phrase is used to emphasize how something should never happen, no matter the circumstances. It's a more forceful way to say "never" or "no, this cannot happen." In this video, Jessica doesn't like the idea of her husband having female friends. She proceeds to tell her husband the rules she has for him when spending time with female friends. One such rule is his female friends cannot be gymnasts, cannot have been gymnasts, nor can they desire to be gymnasts.

Is there any difference in nuance between "pick out" and "pick"? Can I use "pick" instead?

To "pick" and "pick out" are verbs with practically the same meaning. However, "pick out" specifically means to pick one thing from a group or selection of others. The speaker is referring to the action of choosing a "great outfit a week" out of a selection of clothes, so "pick out" is more appropriate in this context. Ex: I'm a very indecisive person. It's always hard to pick what to eat at a restaurant. Ex: I picked out the best apples from the bucket.

What's it mean? "human sign?"

"A human sign" here means that [something] is a sign of being human. It is implied in the song that if you close your heart to others after something bad happens, it is normal human behaviour. Ex: Crying when you are sad is a sign of being human. Ex: Missing your parents is a sign of being human.

Can I put "facing burglary charges" after "he"? Like "as he facing burglary charges appeared before her."

You can say this sentence as, "As he faced burglary charges, he appeared before her" or "Facing burglary charges, he appeared before her".

Is "once" necessary here?

"Once" here is necessary because it is part of the whole phrase "once again", which means "one more time". Ex: Although I had noodles for dinner last night, I'm having them tonight once again. Ex: Once again, you don't listen to what I have to say.