Imaginary didn’t click in until I saw it as “behind the paper”. So, you get your x and y in front, and your imaginary is jutting backwards.
But, by tradition, we rotate it and show the imaginary in front and push the y behind the paper, so we end up with x going from left to right and imaginary from up and down.
Until that ‘clicked’ , I was totally baffled by imaginary.
[it’s also called the z-plane] I hope I don'[t have it wrong but it’s how I see it.