Can revenge ever be good therapy, like flirting with his best friend or spreading a nasty rumor about him?

The best revenge is getting on with your life and living it to the fullest. Because you're doing it for you, not somebody else. Greg once dumped this woman and a year and a half later, he saw her on the street. She looked terrific and was with a total babe. She never called him after it was over but clearly had moved on with her life. That's the way you would want to be seen. Don't hound him with IMs, break into his e-mail, or hook up with him when you're both lonely at 2 a.m. hoping you'll get back together. Keep your dignity intact and set out for the new direction in your life. That's the best way to get back at him.

 报复会不会是个好的治疗办法呢，比如和他的朋友调情或者散布对他不利的谣言？

最好的报复方式是过好自己的生活，让自己的生活尽可能的充实。你这样做不是为了别人而是为了自己。格瑞格把某个女人甩了，然后一年半后又在街上看到了她，她看起来好极了，还有个理想的情人和她在一起。分手后她从来没给他打过电话，但很清楚她过得很好。这才是你应该想要的结果。不要给他发信息、不要非法进入他的电子邮件、不要在凌晨2点你们都很寂寞的时候打电话给他说你想要和好。要保持自己的尊严，开始新的生活。这是最好的报复方式。