Earlier quoted context omitted.
I visited Ireland this year (+- the Wild Atlantic Way), we considered biking but I'm happy we eventually decided to hike/hitchhike/take buses cause Ireland is not designed for walking/biking. Everything's fenced, roads have crazy high speed limits for their width, there's no pavements outside cities, even forests are banned most of the time. Hitchhiking on the other hand was great - we waited for more than 15 minutes…
I wouldn't necessarily say that's true for cycling. You just need to choose your routes carefully - follow the minor roads, not the major ones you'd use in a car. I've had some lovely days cycling quiet country lanes in Ireland. Same applies in the UK, though there are some areas (principally the Home Counties) where it's difficult to find a road that isn't infested with speeding Audis.
Anyway, I don't want to complain too much, it was still great. The nature is superb. Just hard to get around without a car.