It was signing Defoe that started it, in my opinion. For them, that was the starting point where we got their best player while they were a Championship (or was it called the first division back then?) club, and they wanted to be us at that point, and hated us for taking their player. They wished they were the big club taking the small clubs asset. Then they got promoted and we actually played each other being in the same division. After some yo-yoing they established themselves, just about, as a Premier League side. Thing is, we kicked on ourselves and started challenging as a top team in the league and in Europe. They got a new stadium, a shit one. We got a new stadium, an amazing one. The gap between us has basically remained the same and we are still what they wish they were. They are full of jealousy over us. To us though they are just an annoyance. I've come on this thread bored and after reading each of the threads about our real rivals first. How can we care about them when we're challenging the big boys for titles?
That gif above with the the dog waging it's tail sums it up perfectly.