Margins shrink. Cash feels tighter. Decisions that used to feel easy suddenly don’t. And while revenue might still look “fine” on paper, the bank account tells a different story. This isn’t poor management. It’s the result of several slow-moving financial pressures hitting at once, many of which accelerated over the last two years.

There’s nothing quite like opening the mailbox, seeing an envelope with “Internal Revenue Service” printed on it, and feeling your stomach drop. Even people who are perfectly organized — even people who’ve done everything right — feel the same jolt of panic when they receive an IRS notice.

Most people think their financial professional focuses on the past: last year’s tax numbers, last quarter’s profit, last month’s expenses. That’s the compliance world. It’s essential, of course. But it’s focused on what already happened.

Taxes are usually dull. But every so often they spark something strange, from performance-art protests to digital revolts to tractor blockades. Here are five tax uprisings that broke the mold over the last 100 years.