Negative buffs speed up timers for positive buffs...

When a Sim has a negative emotion buff there are things we can do in-game to speed up the timers and end the buffs sooner. If having a negative buff sped up the timers on positive buffs it would make the negative buffs more powerful/impactful. 

If your werewolf Sim does mind concentrating yoga for the 8 hour focus buff and then the Hungry Like The Wolf temperament kicks in and you get the 2 hour Sudden Craving +4 angry buff you focus buff would tick down at a faster pace. 

You could also make it so a +4 angry buff would tick the timer down faster than a +1 angry buff. 

This way negative emotions could be something you have to deal with instead of just work around.