4. You're being gouged
According to IbisWorld, St. Patrick's day beer consumption in the U.S. amounted to $245 million. They also estimated 2.1% growth within two years, which would bring this year's take to $255 million. That's great for bars and packaged goods stores, which make 1% of their beer sales on that day alone, but it's not great for the rest of you who are paying whatever holiday price a bar chooses to charge.
It's hard to blame them. Considering that 30.6% of consumers surveyed said they planned to hit a bar on St. Patrick's Day, any increase in price could be considered combat pay for dealing with the abrasive, slow-ordering, second-guessing, non-tipping amateurs who opt to play publicans for a day.
Oh, and those St. Patrick's Day pubgoers tend to be these folks ...