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.
I bought an Ember mug because I thought it was silly. I ended up really liking the temperature control. I don't rush my coffee/tea. Now every sip is as hot as the first one.
The new Ember costs, I think, half again as much as the first iteration. It's a cute gimmick but I certainly wouldn't pay what they're charging now.