Yes, it is very rewarding to program your own graphics routines or your own simple implementation of a raytracer and then see the correctly rendered scene on screen for the first time.
It's so cool: A scene that took 10 minutes to render in 1995 - nowadays you can see that scene through a moving camera raytraced in real time in your browser!
I did this on my Amiga a lot time ago (1995), and then re-created the feeling using ShaderToy: https://www.shadertoy.com/view/lds3z8
It's so cool: A scene that took 10 minutes to render in 1995 - nowadays you can see that scene through a moving camera raytraced in real time in your browser!