Most Helpful Girl
The best 'revenge' on my ex who cheated on me was nothing spiteful in the slightest. All it took was my simply finding someone i was much happier with overall, and who was able to give me something my ex had never managed to accomplish, even pre-breakup.
Most Helpful Guy
"Living well is the best revenge."
Don't let a setback break you. Pick yourself up, dust yourself off, adopt a positive attitude, and re-double your efforts to improve yourself and seek what you want. Learn from your mistakes, be humble, but work harder and be willing to change your thinking and your behavior. Find people who are successful, learn WHY they are successful, and emulate that behavior.
"Revenge" will take care of itself, without you having to do anything at all specific to that "revenge", if you follow the above tenets.