Quick note: during this trip I’ve been through both Northern Ireland and the Republic of Ireland so when I say “Ireland” I’m talking about the island.
This might be a good time to mention that Northern Ireland uses the Sterling pound (being part of the UK) while the Republic of Ireland uses the Euro (as a member of the EU). The speed limits in Northern Ireland are in miles (since they use the Imperial system) while the signs in the Republic of Ireland are in kilometers (because they use the non-retarded system AKA metric) but at least they both drive on the left side of the road.