Whoever coined the terms ‘complex numbers’ with a ‘real part’ and ‘imaginary part’ really screwed a lot of people..
Usually they explain it something like: oh, at first people didn't know what 2-5 added up to, but then we invented negative numbers. Well, complex numbers are that but for square roots of negative numbers.
But that's a completely misleading way to explain these things. Complex numbers aren't numbers aren't numbers really.
If the square root of -1 is not a number, what is it? How come you can do arithmetic with it?
As one broadens the idea of what it means for anything to be a number, we acquire/invite new members to the family and with great benefit.