There are three days in the Irish year on which it is traditional in to have a convivial drink.
St. Patrick's Day, March 17
There's nothing complex or mysterious about this one. The towns and cities will have a parade early in the day. This is the celebration for the patriotic-, historic- and religious-minded; for the kids, and for those who don't mind large crowds whilst sober.
In the evening, people drink. It's pretty straightforward. It's a mess.
March 17th is also the beginning of fishing season. It can be a good night for cider and hashish riverside with a fire.
The sale of alcohol is prohibited on Good Friday. People grumble and moan "what's good about it?" But others like it this way and enjoy the adaptations. It's normal to celebrate the day amongst friends at somebody's house. Some say they would miss the alcohol ban if it were lifted.
Saint Stephen's Day
The day after Christmas, a day with family ostensibly religious and a day on which the pubs were closed. December 26th is a time to drink with friends in the pub.