I work in IT with a large part of my job being security. The company I worked for at the time was a constant target of attacks, especially social engineering, since they've been successful a few times. The company was a good target too since almost everyone had a company card without any real checks on purchasing until your submitted your expenses. We've had more than a few times where an HR assistant, front desk person, or executive assistant bought gift cards. Even after hours of mandatory training, sometimes you just can't fix stupid.

It was a company in the beer industry with a CEO who had a distinct German accent. He grew up in the US and Germany and his voice was very unique with him dropping a lot of the harshness of his accent. He was very soft spoken unless you were in trouble, and then the were-talking-business German accent came out lol. It was a very distinct accent with his tone and I could spot it in a room of crowded people easily.

One morning I get a call from our DC office. No caller id, just recognized the number (which was a red flag) and when I answered it was the CEO. 100% perfect accent, tone, everything. There was a problem though, I leaned my head out of my cubicle and he was just down the hall without a phone in his hand. I asked some questions to see how quickly "he" would respond and there was no delay, no change of tone, nothing.. it was near perfect. I started asking a few questions about business stuff and got hung up on, but it was the first time I've experienced something so accurate. Its scary the how fast the tech is moving along.