It would appear that overtaking is a manoeuvre to be attempted at every opportunity: on a bend, on a hill, when the car you're overtaking is overtaking another car, into oncoming traffic, and along narrow one-way streets. It would also appear that it is compulsory to drive as fast as possible while attempting these, or any other manoeuvres. Unfortunately, many of the roads are not only narrow but badly surfaced, and full of drivers that never took a test. This was due to a massive waiting list in the late 1970s causing the government to issue a full licence to anyone that asked for one.
It seems the only really important thing to remember when driving around Ireland is the subtle form of greeting that is also common in rural areas of the UK (particularly in the Midlands). When one comes across a farmer travelling in the other direction on foot they will, out of politeness, raise their index finger by way of greeting. The driver should respond by raising the index finger of their right hand while keeping the entire hand on the steering wheel.
It is common for regular drivers who know many people in certain local areas to save time, and drive with their index finger permanently pressed to the windscreen in a continuous greeting mode.