Even on the Gameboy things aren't quite as simple and self evident as all that, for example from another thread on this post: when the Game Boy's screen is rend

Even on the Gameboy things aren't quite as simple and self evident as all that, for example from another thread on this post: when the Game Boy's screen is rendering (i.e. almost all the time), the CPU doesn't have access to VRAM. [...] writes are ignored, and reads return garbage. So one of those platonic store instructions might actually be a no-op; you can't tell by looking at it in isolation.