Charlie Harrington: Mario Paint Masterpiece
There's just no reason for this game to be this good. Sure, MS Paint on Windows was always a fun time-waster back in the day. But it certaintly wasn't weird. And Mario Paint is w-e-i-r-d. It's like Photoshop on Magic Mushrooms. Plus an animation studio. Plus a digital audio workstation (aka Garageband). And all this back when we were still recording our favorite songs from the radio on cassette tapes (if we were lucky enough to catch them, and even then usually missing the first few bars).
Don't talk to me about delightful UIs or UXs if you haven't played Mario Paint. Nothing makes sense at a glance. Instead, it's pure discovery. Click-and-see. The undo button is a dog's face. Why? Why not. The fill-paint animation is a break-dancing paint-brush with a smiley-face (that sentence had a lot of hyphens). I spent hours and hours clicking every button in Mario Paint, and just making weird shit.
Nintendo are (clearly) not the gods of UI, but in Mario Paint they are playing near the upper echelons of what "UX" can mean. Undodog is a character, and if you idle, he will start to walk around restlessly, hurrying back if you return, and sneezing in the background if you turn off the background music. (And Nintendo wouldn't be Nintendo if he didn't also reappear in Super Mario Maker, which shares a lot of conceptual DNA.) Clearing the screen is done by flying a rocket across it; saving involves a robot. Not to mention the music creation genre it inspired, or the mouse affinity tutorial turned mini-game.
I'm not saying all software should be designed this way. But when it comes to intentionally quirky and weird UIs, most drive you up the wall. Mario Paint manages to tell a story, encourage creativity and facilitate said creativity (within significant technical limitations, which it leans into). Look at the cover art – Mario is doing that thing where he measures proportions, but even this has a double meaning, where he winks, smiles and shows a thumbs up to what he's creating. The kid using Mario Paint is not being helped by a well-meaning, self-aware parent, overseeing the puerile paint splashing with portent; they are simply doing what Mario is also doing.
Many modern UIs see it as a goal in itself to strip everything down to their bare essentials and then freak out when there are no more essentials to clear out or conceptual purity to further. The opposite is to really empower your users, by giving them tools that let them do things they probably want to do, instead of worrying that an errant distraction will ruin everything.