I bought a piece of 1.5 inch stiff foam to try to fix a sag in a bed. It didn't work but having that thick piece of solid foam around has been a life saver.
Need something flat to put a laptop on? Throw it on the foam. Going to be doing something that requires you to be on your knees for a while? Get the foam!
It went from stupid purchase to something I'd gladly replace if it broke.
When Teavana still existed, I bought a teapot and some "teas" (Teavana was mostly herbal tisanes...but still.)
I don't drink coffee, so I imagined the teapot wouldn't ever be used...but somehow it ended up being a big hobby for me. Bonus: fancy teas from online stores are cheap to ship, because they're basically dry and lightweight. Like, if you want to become a food snob about anything? Tea really is the way to go.
The one learning curve I had (as an American) was learning that you DON'T steep the tea longer for stronger tea. You use more tea leaves/more tea bags. Steeping too long turns the tea bitter. (I thought I disliked tea when younger b/c I'd only ever had cheap tea bags left to steep for far too long.) Also, when brewing a green tea, they're really reactive to boiling water, so you REALLY don't want to use boiling water or it'll be a bitter mess. You want to either boil then let it cool, or get a fancy electric kettle where you can set the temperature so it's appropriate for green tea, oolong tea, or black tea.