Woobag

A word used to express surprise, angst, disappointment, joy, excitement or scandal.

It is very multi-faceted, and if said in the right tone, can be used for any situation.
Pronounced: wuh-bag

Policeman: "sorry ma'am your cat has been runover"
You: "oh woobag!"

or

Girl: "omg i just slept with the hottest guy"
You: "woobag!"

or

Teacher: "Zac Effron will be visiting college tomorrow"
You: "WOOBAG!"