How does a woman get her revenge on the man that let's her down? Simple, hit him where it hurts - his car.

The first strategy is to simply lock him out of his prize possession;

Another strategy is to deface the car in a way that makes her complaint somewhat obvious.....

Or, if really really pissed and angry then both deface and damage it....

Of course, she can always 'mark' his territory too if she feels like it...

Then there is the strategy of making sure that he knows that she truly hates him and wants to do him serious harm...

Bust most effective is to ensure that the car is pretty much unusable and marked with something - well - both meaningful in terms of expressing her feelings as well as truly insulting and malicious. The ultimate in revenge strategies....