For me it’s driving while under the influence. If you couldn’t tell, I like me some ganja. However I have long since held the belief that it is utterly insane to drive while under the influence of most substances, with maybe nicotine and caffeine being the exception. All too often I see other stoners smoking and driving, which I simply can’t fathom. I’ve only operated a vehicle once under the influence and it was just to move a U-Haul around the block to a different parking spot, which was such a scary experience while high that I refuse to even consider getting behind the wheel again while high.
Regarding backpacking: I experienced the ultralight community to be a very friendly and welcoming (although a bit nerdy) group of people. Yes, you CAN spend a lot of money on hightech equipment like many people do in cycling, archery etc. but it is also very common to MYOG (make your own gear). You can spend 200 bucks on the latest leightweight highend titanium cook pot. Or you can simply reuse an old fish can to cook in. And while this selfmade gear sometimes looks a bit clumsy, it often beats the hightech stuff. And the lightest gear sets I’ve seen were mostly self-made.
When I started backpacking I was just a poor kid going with my Boyscout group. I used a WWII rucksack, carried canned food, and had a crappy $5 BSA mess kit. I had cheap boots and always got blisters. I still had tons of fun.
It’s worth pointing out that good gear will last you decades if you take care of it, so it’s one hobby where spending extra can actually make sense. I just finished replacing my last piece of equipment with ultralight gear last year. Now my whole setup is UL. It definitely makes trips more enjoyable, especially now that I’m middle aged. But I see young people drooling over some lightweight tent that costs a bajillion dollars, and I’m like “dude, you’ll get better performance from eating fewer cheeseburgers”. LOL
You’re right that you can make some pretty sweet equipment if you’re willing to learn about it and take the time to craft it. I made a lot of gear substitutions when I was first getting into UL, like using aluminum instead of titanium, and stuff like that, but I never did make any of my own gear. That always intimidated me, so I’d just be really strict about what went into my pack to keep the weight down, until I had enough legit gear to splurge my weight allowance for something like a camp chair.