A Snowflake's Guide to Dealing with Criticism

First, say "Thank-you"
Yes, I know you are offended. I know that nobody at Expensive University treated you that way. News flash: You were paying Expensive University $30k a year to deal with your BS. Your boss is paying YOU to deal with his BS.

Your adrenaline is responding to the words, the tone and the body-language. Your boss has given feed-back to other snowflakes and is a bit jumpy. He does not know how you are going to respond. You can defuse much of the tone and body language with the simple words "Thank-you."

"Thank-you for the feed-back." Great first line because that is how your boss sees it, as feedback.

Other good choices are:
"Thank-you for calling that to my attention."
"Thank-you for the guidance."
"Thank-you for not letting me make a mistake with a client."

Repeat the feed-back the way you think it applies to your job and how you failed to meet the client's needs
"I want to be extra sure I heard you correctly because sometimes I get stuff mixed up. First the beef patty, then the pickles, then ketchup and finish with the mustard before putting on the top of the bun."
"I heard you say that it is very important that everything I write is in Times New Roman, 12 point font because the client values the fact that I am part of a large law firm and they are represented by more than Joe Doakes, Junior Attorney; they are represented by the entire, seamless firm."

Then plead ignorance if it applies
"I was not aware."
"I like the challenges of this job but there is a lot to pay attention to."
"I am still working on figuring out how all the rules and directions apply on a case-by-case basis."

Promise to do better in the future
"I will be more vigilant in the future."
"I will make notes so I won't make this mistake again."

Practice.
Your boss will give you feedback at the end of a long shift. He will be tired. You will be tired. He won't have the energy to candy-coat the feedback.

You will also get feed-back at the end of the shift from the shift that follows you. That is the only time they will see you. You may have left things in a way that set them up for failure. It may even be the way the shift before you left the system.

"Thank-you for the feedback. I heard you say that leaving the work-station a mess made it difficult for you to organize your thoughts. I did not know how much it impacted you. It will help me if you take a picture of how you want the work-station set-up and post the picture. I will do my best to leave it set-up that way."

You need a script that will spill out of your mouth with no thought or effort.

Practice when it matters. Practice when it does not matter. Practice when you put the toilet-paper on the hanger wrong. Practice after you drink your room-mate's last beer or leave the toilet seat up.

It will save you a pile of work in the long run. You won't have to create a script when the boss is going off on you and you won't have to bury nearly as many bodies.