It is customarily to put on green clothing on Saint Patrick's Day. The reason why green is worn during the celebration is because legend has it that when you wear green attire, leprechauns can't see you. And when they can't see you, they can't pinch you.
Answer: St. Patrick
St. Patrick (who is also called the "Apostle of Ireland") was a Christian missionary known for introducing the people of Ireland to Christianity. He reportedly did this in the AD 400s.
Answer: All Saints' Eve
All Saints' Eve is not another name for Saint Patrick's Day. It is rather an alternative name for for Halloween. The following are alternative names for Saint Patrick's Day: Feast of Saint Patrick, Lá Fhéile Phádraig, Patrick's Day, (St) Paddy's Day and (St) Patty's Day.
The Lutheran Church and the Esatern Orthodox Church also venerate St. Patrick.
Answer: A tree
There are Irish legends which say that St. Patrick stuck his walking stick (made of ash wood) into the ground at a place he went to evangelize. The stick later grew into a tree.
Answer: United States
The first St. Patrick's Day parade is reported to have taken place in New York City, United States in 1762. It wasn't until somewhere in the 20th century that these parades started being held in Ireland.
Answer: The Shamrock
St. Patrick's Day is widely represented by the Shamrock. This is a three-leafed plant that according to legend was used by Saint Patrick in explaining the concept of the Christian Holy Trinity to pagans from Ireland.
St. Patrick's father was a deacon while his grandfather was a Christian priest.
Despite its strong religious undertones, St. Patrick's Day is one of the most famous drinking holidays in the world. According to reports, the sales of beer increase by over 150% on this holiday. And of all the various brands of beer, Guinness is the most consumed during this celebration.
Answer: You're pinched in an affectionate manner
Traditionally, everyone is required to put on green colored clothing and accessories on Saint Patrick's Day so that they become invisible to leprechauns (who can't see green). And since leprechauns like pinching people they see, those who don't wear green are accordingly pinched.