I was trained many years ago to eliminate any trace of a regional accent from my speech. Why? Simple, I was an Air Traffic Controller and way back then we were taught to speak so clearly that anyone could understand us without having to repeat what we said. That means, obviously, getting rid of any regional speech idiosyncratic patterns.
The basic concept is: no one can tell where you are from when you speak. I continue to try to make my speech as clearly understood as possible. I wish everyone felt the same way. Unfortunately many, if not most, people want to emphasize their regional speech patterns. Give me strength!!! It isn't cute people, it's idiotic.
Speak clearly and without accent and you will succeed in life. Lapse into regional idiomatic speech and you will fail.