I was running and for whatever reason I remembered one of the more common excuses I received from a girl in my dating days, specifically back in high school and college;
"My friend just broke up with her boyfriend and really needs me right now."
This excuse is usually delivered when you have a date with a girl and she really doesn't want to go out with you. It's a "perfect excuse" in that it's palatable enough that if you accused her of lying she could feign indignance (and at the same time accuse you of "creepystalkerassholishness" PROVING you weren't worth her anyway, jerk!), but is outlandish and over-used enough that it sends clear signal not to ask her out again or reschedule the date.
This remembrance then sent me down the path of excuses I've heard:
"I have to work."
"I have too much homework."
but the "my friend just broke up with her boyfriend" excuse was so common (not to mention lame) I believed it was part of a group of "well-known" or "standard" excuses women are trained to use.
Ergo, I think it's high-time to catalog the "standard" excuses and their English translations/meanings so young men know what to do when they receive such excuses. This list will then be updated as we receive more "standard" excuses. You may start listing them off now. Please forward this link so we can get the most comprehensive group possible.