Liverpool FC. More so their deluded and cult-esc support.
The coach wrecking by the Dippers, aided by LFC and Merseyside
Police, is something I will never forget or forgive. That went beyond even hating United.
Add that to the the new found hatred of City from the Coach Wreckers, albeit because City stopped LFC from winning 2 PL titles. Prior to that the Coach Wreckers loved City bar the Manc tag. 6 easy points every season. And City fans hated United as much as Liverpool fans hated United, so we had that in common.
Once you add the hacking of City's player database by LFC staff, and the Red Shirt cartel, which includes LFC, the reasons to hate them the most are obvious.
Now I hate everything about LFC. especially their fans.