Catalysts bring many consequences

Many stories need catalysts to get the action moving. Someone needs to get sick. Someone needs to lose their job. Someone needs to die.

Keep in mind, however, that such huge catalysts come with serious consequences.

You can't get cancer without losing strength and dedicating a lot of time to getting better. You can't lose your job without having financial survival be a key consideration until a new option emerges. And, of course, you can't die without stopping any action on your part.

When putting a catalyst in your story, make sure you are really thinking about the consequences. Other than setting off the action you want to see, what other changes is your catalyst causing? Don't leave your readers asking this question in confusion.