Also if you read Henry IV parts I and II (and Richard II) you get a really strong sense of the pressure to establish a dynasty and secure your position. With lots of important nobles jostling for position, the person sitting on the throne is never really that assured.
Henry IV becomes king when Richard II was deposed, but has to carry the guilt of having deposed and ultimately caused the death of an anointed king. The whole of his reign is about trying to secure his position whilst also wanting to shed the guilt (he wants to go on a pilgrimage to try and rid himself of the guilt but never manages it).
I also remember learning at A Level that the northern nobles like the Percys were so powerful in their own region, and it was so remote from London control, there was a good chance 'Northern England' might have broken away as a separate country (and stayed catholic).
Can you imagine what might have been since then if it had happened? Where would be border be? What would be the northern capital? Who would be winning all the Olympic medals and football trophies, North or South? Rugby would obviously split on union/league lines so that would be quite straightforward ...