I grew up and raised in Osaka, so I speak Osaka dialect. I have a pretty thick Osaka accent. When I had worked in Tokyo, I was struggling to speak standard Japanese. People have a prejudice against Osaka dialect speakers. They think Osaka people is more friendly than Tokyo people, but They are less polite than people in Tokyo. Osaka dialect come across like that. So, my boss lectured me not to use Osaka dialect in case our client do not irritate because of my accent. I paid attention to speak standard Japanese. But, it did not roll off my tongue.  My boss said that I got used to speak standard Japanese. I could not sink in yet, but when I touched base with my parent, she told me not to talk in standard Japanese. I realized that I became standard Japanese speaker.