If you keep taxes at 0% then increase the taxes to 99% in December, you get the max back in yearly taxes, but if you set the taxes back to 0% in January, the population doesn't really get upset or leave. This makes earning money way too easy. I find that the population in my towns get angry and leave when I set taxes above 6-7%, but they're okay with 99% taxes once per year.
If you keep taxes at 0% then increase the taxes to 99% in December, you get the max back in yearly taxes, but if you set the taxes back to 0% in January, the population doesn't really get upset or leave. This makes earning money way too easy. I find that the population in my towns get angry and leave when I set taxes above 6-7%, but they're okay with 99% taxes once per year.