Football is full of rivalries. You only have to go down to your local Sunday league team to see that. If you know anyone who has children from the ages of 5-16, they will tell you, and indeed many children themselves will tell you which teams they want to beat the most, whether that is due to the locality of the opposition, the players who they know and may or not dislike, or past games.
It is however, these differences, these frictions, these two embodiments of beliefs and ideals which gives sport, and football in particular, an added level of intensity of sorts.
There is even the aspect of wider, political and religious issues and implications surrounding these rivalries, where things are taken to much extremity. Take the long running feud's between Scotland's giants, Celtic and Rangers, bounded by the divide between Protestants and Catholics, or the history of El Classico, the late Spanish dictator, Franco's Real Madrid, against the rebel army, represented by Barcelona.
England is full of great rivalries, Merseyside is shared by two of the countries most passionate clubs, London has Tottenham Hotspur vs Arsenal, Chelsea vs Fulham and West Ham vs Millwall just to name a few and the Midlands boasts the black country derby.
Yorkshire provides plenty of animosity between the likes of the Sheffield clubs, and the much disliked Leeds United, while Lancashire plays host to Blackburn vs Burnley, seen by some as the world's oldest rivalry, as well as the Manchester derby. And that is just a small number based upon locality. Take simply into account, bad blood built up over time and you have the mutual hatred between Chelsea and Leeds and the more recent contrasting styles of Stoke City and Arsenal.
Arguably the greatest of this feast of clashes is Manchester United v Liverpool, the two giants of English football and two of the greatest clubs on the planet.
This clash is more than just the tale of two cities or of two ideologies. The ideologies, in fact, are much the same. Both clubs have a tradition of promoting and continuing attractive, attacking football, an aura around the ground which drives fear into opposition, and crucially, a drive and willingness to reap consistent success.
Liverpool may have had less success in recent times, yet the history is there, as is the desire. After a good run of form, Manchester United will be looking at Sunday's game as final confirmation that they can start to be taken seriously again, if not as title contenders then at least by gaining Champions League qualification. They will then be able to reclaim at least some of their old status and not sink into the abyss of what a club of its size could only call mediocrity, as Liverpool did after the success of the 70s and 80s.
As it turns out, the Anfield faithful will be the one's feeling the heat this weekend, as performances just seem to be declining further. Liverpool are sinking, and sinking fast. A win at Old Trafford may just provide the confidence boost needed to prevent serious problems from unfolding.
The timing of this great occasion is what makes the derby, the ever more exciting. Although not making or breaking either side's season, the game does represent a moment that could have a huge impact on how each perform over the next few months.
Both want to get back up on their perch, who will it be?