Psychology
The Peltzman Effect
Give players a safety net and they will play recklessly enough to need it -- safety features do not reduce risk, they redistribute it.
Technology
Deterministic Simulation
If two computers run the same inputs in the same order, they get the exact same result -- no exceptions, no floating point surprises.
Consoles
Sega Dreamcast
The most beloved failure in gaming history; it did everything right except survive.
Iconic Games
Galaxian
Space Invaders learned to dive-bomb, and the shoot-em-up genre got its first real evolution.
Esports
Ranked Anxiety
The paralyzing fear of losing rank points that stops players from actually queuing up and playing.
Based on infomaxxxing codebase