The worst

Nuclear weapons
Unannounced pickles placed on plates without warning or permission
The Trump Presidency
Dress codes
Identity theft
The second and third Matrix films
Dance school teachers who perform in their students' recitals
The end of summer vacation
Incarceration for minor drug offenses
Parents who disown their children for choices of spouse or religion
The gun show loophole
Off-brand Pop Tarts
This sign

Things that should not exist in this world.