I've been playing Irish music most of my life and have to say I also used to play too fast when I was younger. Part of this might have been copying the style of some well-known players in the 70s and 80s when speed seemed to beome the fashion.

As I've got older I've consciously tried to slow down the tempo of a lot of tunes... bounce and lift being more important than speed. It's also difficult to play tasteful triplets and other ornamentation if the tempo is too fast.

Now I live in Scotland I've noticed the tendancy to speed with Scottish music too, especially with some younger players (though definitely not all).

Zen