We lived in South West of city center, and Sun office is North East of Dublin, there is about 5-6 kilometers, not very long compared in Beijing. Here I'm going to show you how to get to office daily.
The normal route happened everyday:
Apartment -- Tara street dart station (by foot, 20 mins)
Tara -- Clontarf Road (by dart, 10 mins)
Clontarf Road -- office (by bus offered by East point park, 5 mins)
Count some waiting time, almost spend 50mins.
The best traffic tool is by foot, what we Chinese say 11 road. Traffic is not good, maybe big city always has this problem. We walked a lot, almost 5 kilometers in total one day. I do not think it is a bad thing, we can meet lots of things on the road. People here walk very fast, whatever man or woman, I could not catch at the beginning, but now, heihei, I'm one of them.

Two layer bus is special in Dublin, we bought a monthly adult ticket, it servers train and bus. Almost each bus will go to city center, where is bad traffic and I need not go there for work. Interesting thing is bus stop board only shows several big stops, for visitor like me, I must ask each bus whether they go to my place.
There is tour bus, this will take you almost every popular attraction in Dublin every 10 mins, very convenient. But I did not take it.

We did not take bus much, the most common thing we take the bus happened when the dart is out of service. We only need take 2 stops on dart, but we met more than three times out of service or breakdown. Then we must get off on Conolly stop, and go to city center for bus. Good thing is we can eat Chinese food since we need go across China Town.
See, Zhaozhou and Harry is looking for where we should take off. There are two kinds of trains, Dart is green and Commuter is blue, Commuter does not stop at Clontarf Road, we did not take it.

This is the park bus take us between office and dart.

There is another train on the street called Luas, but we did not take it.