Travel insurance is a very good thing, because it means that there are less things to worry about, except you can add worrying about the travel insurance itself if you are a very thorough worrier.
Worrying about work gets into your sleep, until you are dreaming about what the Remuneration Tribunal might do. Which is hardly worth worrying about even when awake, because they just do what they do. Do do do dooby dooby doo.
That wasn't me, by the way, that was my work mate, who is not such a worrier generally.
Other things you can worry about: illness, assignments, money, if the mould can be scraped safely off the jam, global inequalities, missing the bus, whether worrying gives you grey hairs or only wrinkles, warts. Warts are not caused by worrying. There is no such thing as worry warts, whatever people might say.
Global warming is a good worry option, because it introduces a wide range of second-order worries, including worrying about how so many people ended up being idiots. Or maybe that's more of a wondering than a worrying.
You can worry at knitting, but only if you are a small dog in an English story for children. You can worry about time travel, but it never seems to come to much, so maybe worrying works as a prophylactic after all.