Figured out how to draft myself a curved waistband for a skirt I've been making, and it fit first time! Very proud because I'm not a very experienced sewist and usually just stick to whatever the pattern tells me to do.
More info for those who don't mind being educated about sewing first thing in the morning:
Basically most sewing patterns come with a straight rectangular waistband, but those only fit on people who are relatively straight up and down where the band is gonna sit. Meanwhile I'm so short-waisted and big-hipped that everywhere is massively curvy and there's not a straight up and down bit anywhere to be found on my torso.
So since this one is a wide waistband, there's a full three inches more circumference needed at the bottom of where the band sits than the top. Therefore it needs to be curved, therefore I had to break away from the pattern and do it all myself.
If you can never get waistbands that fit right and everything always gapes weirdly, you too may be cursed with curves. I recommend learning to sew.