My dad was a huge Larry Bird fan growing up, so I've always been a big Celtics fan. However, being a kid in the Midwest in the 90's, it was hard to really follow the Celtics. I didn't really start following the Celtics closely until the Big 3 formed, because they were hardly ever on tv.
Honestly, though, my outright obsession with the Celtics coincidentally came about in the season of 2011-2012 when I broke up with a long-time girlfriend and needed to find a new passion. Thus, I got league pass and have only missed about ten games since the 2011-2012 season.
I must say, this year's team really rivals the 2012 team as my all-time favorite Celtics team just due to their underdog mentality and the way they seem to prove everybody wrong.