I feel pretty bad that you have taken something I said in rather a different spirit from that intended.
It's not the first time I've delivered a kind of 'pull your socks up, son, COME ON' type #rousingspeech and I thought you would have understood where I was coming from. I am sorry that it did not.

It rather missed the mark with you today and I'm also sorry if you really feared for your safety/ thought I was going to hit you :/

Yours, somewhat bewilderedly,

UP/PO (small female, not terribly punchy)