Ireland has gone through much in its long history. There are many factors that played a role in the current Ireland that we see today. However, some things had a larger influence than others. It is generally accepted that the Famine of 1845-49 had one of the greatest and long lasting impacts on Irish culture and society. .
The Irish Famine is unique in a few key ways. The fact that Ireland is a western European nation makes the famine, the decrease in population; extreme poverty and dependence on one crop just an Irish thing. The anger then that was in the hearts of all Irish towards the British was there because you ask yourself, "How can a people have this happen in 19th century Europe?" Many believe the British had done so purposely as a way to exterminate the Irish as a race. This of course was never officially true.
It is sad that the famine happened the way it did because unfortunately it placed in the hearts of most Irish a hatred for the British that still runs to this day. The fact that the British prime minister wrote a story of the Famine and had it end in 1847 demonstrates this point. The British did help their neighbor, but not enough and ended it too early.
Immigration had always been a part of Irish culture. With the practice of primogeniture, or the giving of one's land to the oldest son, the other children were often left with nothing. There was not much else for them to do but to emigrate and try to stake their claim somewhere else, predominately America. The Famine accelerated this beyond belief. In the years during the famine and directly after, emigration had increased to a rate of almost 250,000 per year. That is almost 3% of the population leaving the country each year, and not all of them would make it alive to the place they were heading. People would have to scrape together whatever available money they had and had to try and buy a ticket, then they had to survive the trip.