If you don't know, "Per my last email" is the email equivalent of "Hey a*****e, can you read?". It's just a nice passive-aggressive way of reminding people of something. It's similar to throwing shade throughout an email and ending it with "kind regards." It's a necessary patch for anyone tired of seething in front of a computer but having to be "friendly." Together, we can end the passive-aggressiveness and say what we really want to say.