I'm afraid, my post may not respect rule #2 as in reality it's a multi-purpose tool but one that can only single task too. Allow me to explain ;)

I take all my notes (and drafts absolutely everything) using a pen(cil) and paper, either in a pocket notebook or in a custom-made A5/A6 notebook (nothing fancy but if you're curious its latest iteration is visible here, the post in French but the photos should suffice).

I love this setup a lot more than I ever liked writing on a computer/device. I've been using a computer since de early 80s and I'm a decent typist, most of what I write will end up in a digital form of some sort so it's not like I'm a Luddite. It's just that I prefer the unrivaled tranquility of the pen/paper combo, it's incomparable portability, and both it's slowness and unrivaled speed.

• No distractions, no notifications. No ads. No Fomo.
• No tracking or spying either.
• No batteries, no upgrades, no updates, and no crashes.
• It's sturdy as it can withstand me sitting on it (my pocket notebook is often stored in my jeans back pocket). Heck, even if I teared my notebook to pieces I could probably still use it ;)
• It works well under the sun, when the weather is as hot as a politician's promises of much better tomorrows, or when it's as cold as a banker's heart (when it's that cold, a pencil is probably the better choice compared to fountain pen or a ballpoint pen). And it can be used when it's raining too.

But how can it be slow and fast at the same time? If you can touch type, writing longhand is slower. I'm not a pro typist but I type much faster than I trace words on paper, even in cursive. But this slowness is also a great opportunity to not rush things. And then, that slowness is apparent only because, along the years, I've devised my very own shorthand that makes it so I can write longhand at least as quick as I can type. Plus I can freely mix words and quick sketches using the same pen/notebook.

It's a highly focused tool that beyond its apparently very limited capacity—it can do a single thing at a time only, and it has no CPU and no RAM to speak of... beside the very little that sit between my ears, I mean—that can still do a lot of very different things:

• writing: todo, errands, ideas, fictions, poetry, a love letter, or just an address. And so on.
  *drawing/sketching. Depending the paper, one can also do watercolors or gouaches.
• Do some math.
• play games.
• Quickly draw a map/plan to go some place.
• keep info you need,
• It can also be used to share info... by removing a sheet of paper (say, the love letter you just wrote) and give it to someone (no that was not how it all started for little kid-me back then when I was sending love notes on pages, whose pages I teared of my composition notebook, to my sweetheart while we were both very intensively not listening to the teacher :p
• And it can also do origami quite well, if you're into origami.