Well, it's Saint Patrick's Day around the globe. Many people will be drinking their green beer, wearing goofy-looking hats, and at least pretending to be Irish. Ironically, this day of general debauchery is in celebration of an Irish Catholic saint who lived from 390 to 461 AD (though the exact year is questionable, since our modern dating system was not developed until 525).
Green is a colour long associated with Ireland and the shamrock. However, it is not the traditional color for St. Patrick. It began being associated with this day some time in the mid-1700s, most likely to show Irish pride. In the 1800s, wearing green was a symbol of rebellion and could be punished by hanging. While other countries associate green with this holiday, Ireland does not.
If you want to show your true St. Patrick's Day spirit, you should wear blue.
Blue and gold represent the "Ancient Colours of Ireland". They are believed to be the colours worn by Saint Patrick and are still found on the Dublin coat of arms.
So if you see someone being attacked or ridiculed for wearing blue instead of green today, take a moment to correct the bully. In fact, the people wearing green are the ones who aren't being loyal to the holiday.