Can I just point out with Newcastle and Sunderland it is more than football and it goes back a very long time.
It is a conflict that has divided two cities just 12 miles apart, for more than three centuries.
In the epoch before the 1600s, King Charles I had consistently awarded the East of England Coal Trade Rights (try to contain your excitement) to Newcastle's traders, which rendered the Wearside coal merchants redundant. People died because of it. Coal and ships were Sunderland's raison d'etre.
But when, in 1642, the English Civil War started, and Newcastle, with good reason, supported the Crown, Sunderland, because of the trading inequalities, sided with Cromwell's Parliamentarians, and the division began.
It became a conflict between Sunderland's socialist republicanism, against Newcastle's loyalist self-interest. A purposeful enmity if ever there was one. Unlike rivalries between other clubs, the differences between Newcastle and Sunderland date back to fighting based on the necessity to live and feed one's children, and benefit one's city.
The political differences between the two culminated with the battle of Boldon Hill. A loyalist army from Newcastle and County Durham gathered to fight an anti-monarchist Sunderland and Scottish army at a field equidistant between the two towns.
The joint Scottish and Sunderland army won - and Newcastle was colonised by the Scottish. It was subsequently used as a Republican military base for the rest of war.
And while this is a lucid basis for two cities hating each other, it has, like every other modern-day derby, developed profoundly irrational manifestations.