Remember that University of Washington admission essays are all about personality (or so they say at their site). You may use a great plot twist and start from the negative experience. Sometimes the challenges shape us in a much more prominent way than good times. If you show what great lemonade you can make from life’s lemons, what endurance and integrity you’ve got after the tough times, it may become a very powerful story. You’ll present yourself as a strong and mature personality able to rise and go further towards your goal no matter what. But to achieve this effect you need to focus on the positive sides and lessons learned. The negative experience is just a premise here, not the main reason you need to be accepted into the UW campus family.