What worked for me was :
+2 declare enemy, +2 from view painting, +1 aura from the angry painting. So I made an enemy, then fought with him... then viewed an angry painting and stayed in the 'angry room.'
I had to try a few times but got there in the end. It's not easy when you actually want to do it. That's the strange thing with TS4, when you're not trying to kill them off you can find your sim needing to 'calm down' pretty quickly or it's game over. But when you're trying, well, it just takes ages.
The painting I used to view was a +9 .
* edited: I just remembered I used the memory/photo system to reminisce about an angry memory as well and I had to wait until my sim was 'fine' with no other moodlets before I began.