Just a few notes…
Any idiot can use a gun. Mind you not accurately, but it’s not that difficult a procedure. It’s not possible to hold a gun comfortably in a way that you’d be firing to your left or right. For the most part if you’re handed a ‘gun’ “the loud end” is going to end up away from you.
The delightful “You’re too low skill level to use this gun” is too damn gamey.
As far as “Burning water” is concerned I get that it’s just a metaphor but it’s again, a bad example. If you give a 12 year old a box of mac and cheese, a jug of milk, a measuring cup, a stick of butter, and an oven. They might burn it, but they’re going to get it right, you know why?
There are directions on the back that are in painfully simple english.
Butchering is another one that a skill level doesn’t affect what you /can/ butcher but what you can butcher successfully. An unskilled person might go to hack up a cow and get a great deal of the distasteful parts, but you’re not gonna look at the knife and the cow then go “I CAN’T DO IT. WHAT MAGIC DO THE BUTCHERS USE? WHAT IS THIS WIZARDRY?!”
Electronics and computers are a bit different. Disassembling it might work some of the time with no skill, but you risk breaking something while doing it, or being unable to put it back together. Computers are a similar thing, if you don’t believe me, do a quick search for people who’ve “Sped up” their computer by “deleting system32”
Driving would be hit and miss, most modern vehicles have automatic transmission, all that fancy crap. A “new” driver /might/ be able to learn, but struggle. Especially at high speeds, in the rain, etc.
Tailoring is tricky because at most you’d “fail to repair, but waste lots of thread” I don’t really see how one can make a hole worse with a needle and thread, but that’s just me.
Mechanics is complicated. Some things are relatively simple provided you’ve got a handbook of some kind (Changing a belt?) and welding, once it’s using a “fuel” (I think someone said something about welding rods?) could have a “You attempt to weld the part onto your vehicle, but it doesn’t hold and falls of.” It’d also work with Duct Tape “You attempt to duct tape the frame on, but it’s far too heavy and falls off”
I don’t know if I’m missing any skills here but you get the point.