When you meet someone that you like as a person, only to find out that he is a Lakers fan, and then, well, all of a sudden it's hard to see any good qualities whatsoever.
When you wept tears of joy on June 17th, 2008. And, you spent the entire day on the 18th, feeling like you were living in a magical dream land.
When you equate important events in your life--like your wedding or the birth of your children--with what series the Celtics were playing in at the time (my oldest daughter was born during the '02 series against the Nets; I will always fondly remember cradling my infant daughter in my arms while the two of us watched the "comeback" game together. I still credit her for that win).