Have I mentioned this lately? I don't think I have. I hate polar coordinates. About a year ago, I was writing a program to do calculations of fluid flow around a cylinder, and I wrote it in polar coordinates because that's the most sensible way to write such a program. And it kept having these things where I needed to convert to cartesian coordinates, and convert back, and convert the derivatives to cartesian coordinates, and keep track of the extra terms that come up when taking second derivatives in polar coordinates, and so on. And so I would periodically greet my advisor with a grumbled "I hate polar coordinates."
What I am working on now is post-processing the results from that program. It converts things to cartesian coordinates fairly soon in the process, so it wasn't being a problem. And then I realized that I needed to calculate the second derivative of the cartesian velocities -- and I needed to calculate them at the points on the polar grid, using the pre-converted polar data.
I hate polar coordinates.
(/me goes off muttering....)