Sunday was the saddest day of my life. I'm a college student in Boston who went to the Bay Area during Thanksgiving to check it out. Everything was amazing until I went to Union Square and my rental car was broken into and the thief stole my backpack that contains my new 16GB Macbook Pro, iPad 2, various passports and etc. It's really sad because I lost around $3k worth of stuff with no hopes of getting it back.
My advice to future tourists: Never leave valuables in the car or trunk.