I made the awful mistake of going on a blind date. Was a friend of a friend's girlfriend, double date sort of thing. I was the only one with a car, so I drove everyone there, when I met her, I was disappointed. To put it politely, she was fat.

My sister called me at that time. I decided to fake an excuse that she was at the mall aswell, and I was going to go say hi. Instead of going anywhere, I got in my car and ran as fast as I could.

It's not that hard to think this up. In fact, you can fake getting a phone call (say the phone is on vibrate) and use that to get away.