I guess that if you were to focus on just "that" (the bad stuff that happened after 2008) it would definitely leave a bad taste in your mouth, so I understand that.
For me there are way too many GREAT memories, even after 2008:
The C's courageous effort, even after KG and Powe went down, in the 08-09 playoffs...Perk averaging 12 pts, 11 rebs, 3 blocks...Rondo starting to show flashes of greatness even then.
In the same playoffs (08-09) Glen Davis hitting that buzzer beater and almost knocking down the young Magic fan:
http://www.youtube.com/watch?v=BggdtvqKHyILoved it. Yeah we went on to lose that series, but still - the GOOD memories.
09-10 we signed Sheed...personally, I loved seeing him in Green. He played his butt off in the playoffs.
I'd say that this is where Rondo arrived...that CLE series. Rondo was AWESOME. It was BOS that sent LeBron to MIA.
Ray Allen with those 32 points in LA, game 2:
http://www.youtube.com/watch?v=RciLe9SUqVMGlen Davis and Nate Rob in game 5:
http://www.youtube.com/watch?v=kR8PztpCKb0Yeah..we lost the series to LA due to Perk getting injured and some questionable officiating, but STILL....too many good memories.
10-11? We got Shaq. We dominated the first half of the season with Shaq in the middle, and with JO subbing in at times. JO played well for us, IMO, and was our leading shot blocker.
http://www.youtube.com/watch?v=VMNLmS5bVBsHistory will say that we had one the top 10 players of ALL TIME (IMO) in Shaquille O'Neal suiting up for BOS. I remember dreaming of BOS somehow meeting LA in the Finals that year and Shaq giving LA and Kobe problems...it never happened though.
Oh well. Still too many good memories of Shaq and 2010-11.
11-12 will, for me, turn out to be our Swan Song season...but Pierce and KG sent us out in style. We played admirably in the playoffs that year, and KG turned back the clock with this performance vs ATL:
http://www.youtube.com/watch?v=x24elCLzlBw37 year-old KG doing it in the post, LOL - vs Josh Smith and Big Al.
Rondo had those 44 pts, in a losing effort vs MIA, true - but still Celtic-like in his performance. We ended up taking MIA to 7 games, and losing - yes...but:
http://www.youtube.com/watch?v=6GRFYDWsI9UAgain - just too many good memories, even with the misfortune that happened.
Most NBA teams would LOVE to experience was BOSTON has experienced over the last few years.
At the end of our 5 year run our future is looking bright, and we have a good core here, a good coach and THIS guy:

Absolutely no regrets, here...none. Loved the whole journey.