I feel this.
Back in the 90s, there was a fantastic paint program for Mac called ColorIt! (The exclamation point is part of the name, though this is the last time I will respect that because it’s obnoxious; lookin’ at you, Yahoo!*)
It was a commercial product, but ColorIt 2.3 was eventually released as freeware after newer major versions were released for sale. 2.3 was everything I needed, and while I did try ColorIt 4.0, it didn’t click with me the way 2.3 did. At the time I felt like they bowed to the pressure of Adobe’s success and instead of playing to their unique strengths, they made ColorIt’s UI a bit too much like Photoshop. So I stuck with version 2.3.
By the time Mac OS X came around, ColorIt was no longer in active development. But OS X had the “Classic” environment, something akin to an OS 9 VM tightly integrated into OS X. Classic apps didn’t look or feel like native OS X apps, and running Classic came with a heavy RAM burden. But I did it anyway, because ColorIt 2.3 was da bomb.
I continued using ColorIt 2.3 up until Apple killed support for Classic in 10.6 Snow Leopard.
At that point, the intrepid developers came out of hiding and created a Carbon port of ColorIt 4.5 that could run natively on OS X. It was Carbon-only, which meant that it it didn’t run natively on Intel Macs, but it did run thanks to Apple’s Rosetta compatibility layer — at least until Apple axed that as well.
If I ever get into pixel art again, I’ll probably run ColorIt 2.3 again in an OS 9 VM with Sheepshaver or whatever works best nowadays.
*That exclamation point is strictly to emphasize my disdain for Yahoo.