Best:
Firearms: Focusing primarily on 22lr (I have a stash of 308 containing only 500 rounds and I wont buy more), Airgun for practice and for the kids
Upgrades to my workshop: Mill, lathe, 3d printers, welders and all kinds of basic tools and power tools
Skills: Making my own knives with my blacksmith friend, working on scissors.
Transportation: Selling my motorcycle and focusing on my bicycle
Fitness: Commute by bicycle and moderate powerlifting.
Food: Dozens of airtight high quality 60 and 200l steel barrels for secure and compact storage
Worst:
Firearms: Crossbows (Literally useless), Built my own crossbow and created my own bolts (even more useless), Slingshots (complete waste of time)
Workshop: Everywhere I tried to cheap out. Buy good quality stuff even if you plan using it only once a year.
Transportation: Buying a road bike with a carbon frame (Although that was 10 years ago) Steel all the way.
Fitness: Screwing up my back on a poorly executed deadlift. Take it easy.
Food: Chocolate stash (I ate it all)
Intrapersonal: Trying to collaborate with people who believe in chemtrails, flat-earth and lizard people. Don't. They're crazy.
Not sure about those yet:
Investing about 6 grand in cryptocurrencies.
Building my own waterwheel for generating electricity. Spent a lot of money on the project but not useful yet. Vandals destroyed it once where I left it in a stream.
Building my own wood gasifier. Not sure wether I bit off more than I can chew here.
Building my own Steam engine. I'd be better off buying something instead of tinkering with stuff that'll cost me thrice including all the failed attempts. This thing is gonna blow up in my face one day.