PaintTool SAI 1 is my beloved, I don’t care how old it is, I love it and it’s just so comfy to me!
For those who may be wondering, PaintTool SAI is a lightweight drawing program developed by Systemax Software that was released in 2008. The “SAI” part of its name is unrelated to AI, and is an acronym for Systemax Advanced Illustrator. It was developed by one person, Koji Komatsu, and he runs Systemax all by himself. What a guy!