What Joffrey kills and why.
First Ned Stark because he doesn’t want to mix his blood with Sansa. Threatening to gut her little cunt sister was not enough nor was killing her dog.
Then the (unrelated) bastards.
Then the entire city for throwing a cow pie at him. “Kill them all” much like the mad kings “Burn them all”.
Then his half bad blood uncle. (Is he even a Lanister?)
A hooker because he thinks it will hurt his uncle.
All of this might actually be he shipped his good blood sister away.
Joffrey does focus on the bad bloods. Never really see him with the good bloods. Might just be because he likes being evil.
Might marry the South Tyrell just to get away from the North Starks. (I have not seen past season 3) Not that there are any other options.