I was also surprised by the lack of trust and loyalty that they have for one another. I could not undertand why Ferdia didn't believe Cuchulainn. I was surprised by how easily one could be swayed by promising, say, your daughter to them. I would like to think so. I think The Tain should be included in the curriculum.
Irish epic is truly unique.
Not telling the story of gods or other divine creatures, it rather focuses on characters with extraordinary talents. This question is inherent to modern Irish literature. Take Call or Playboy of the Western World. The Tain is surely and enjoyable and unforgettable epic.