So, my question came about because of the impression that I have been given by known completely unreliable exaggerating bullshit artists who told me years ago that the reason the Romans never conquered Ireland was that they were afraid to go up against the lunatic Irish.

Now, as an Irishman, that would be a lovely thing to be able to believe but, I doubt it. So my question has a few parts.

Why did the Romans never invade Ireland? Were we just historically lucky?

If they had attacked Ireland, what type of forces would they have encountered? Would their have been a realistic amount of organised resistance? Who would that have been? What form would it have taken... guerilla style forces or organised, more regimented armies?

I have an almost total lack of understanding of the history at the time, so this could also be a cross post with "Explain it like I am Five", so consider me to be totally clueless and my knowledge a clean slate!