Iconic Games
Mario vs. Donkey Kong: Minis March Again!
The Minis line slid neatly into digital distribution because its toy-box puzzle design was already made for it.
Esports
Smurf Accounts
When high-skill players create new accounts to dominate lower-ranked lobbies, ruining the experience for everyone else.
Mechanics
Crafting Systems
Turning a pile of random junk into something useful -- or spending 30 minutes in a menu to make a slightly better sword.
History
The Loot Box Backlash
EA gave players a 'sense of pride and accomplishment' and accidentally united the entire internet against pay-to-win mechanics.
Psychology
Gambler's Fallacy
You have lost the 50/50 five times in a row, so you are 'due' for a win -- no, you are not, that is not how probability works.
Based on infomaxxxing codebase