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.
My wife and I each thought these were cool but refused to buy these for ourselves. Instead, we got them for each other for Christmas/Channukah one year. It is the best “stupid” gift I have ever got. I have a little Aeropress set up in my office and it’s great. Nothing like coming back to your desk to a hot cup of coffee after you have been away for an extended time. I think they were like $100 when we got them.