DIAGF

1. Die in a Grease Fire. (Sometimes seen as "HUDIAGF" - "Hope You Die in a Grease Fire").

Grease

Hoping or wishing for someone to die in a grease fire is generally considered a harsh way to react to a bad beat or a perceived slight on a poker message board; as explained elsewhere on Poker Terms, a grease fire is very volatile and difficult to deal with.

Based on the severity of dealing with grease fires, "DIAGF" is probably one of the harshest insult acronyms in the poker world, alongside with "YSSCKY," which stands for "you should seriously consider killing yourself."