This is a simple topic. Just list everything in life you hate or strongly dislike.
Here's some things (and people) that really bug me:
Millennials
Hipsters
Emos
Weeaboos
Trumpets
Gangbangers
Racism
Sexism
Homophobia
Ethnocentrism
Animal Neglect and Cruelty
Rednecks
Feminazis
Radical Vegans