When you don't like playing witches for one reason:
The love charm. Pretty much all my witches have at some point 'cheated' on their spouse because they cast the spell on themselves and the next sim they speak to they fall in love with!
Then you have to spend a ridiculous amount of time just trying to make them just friends again.
I get the betrayed moodlet too.... Then I don't really want to play the cheater anymore (can't believe he/she cheated on 'sim' etc).
That and I specifically bought a new computer at the time because my old one would not cope with the graphics etc on TS3.