I will be tuned in to celebrate its demise for sure. SO happy this show is ending, it has not been very good since Carrell left. Not bad enough to force me to stop watching, but it's been an effort to keep up this 10 season committment, especially lately.
There are plenty of problems you can point to, but in general I think they fell into the Seinfeld trap where the characters intially seemed quirky and amusing but gradually over time became pretty loathsome and unappealing. A lot of the early sweetness of the show was replaced by cynicism and snark. Everyone began back-stabbing, sleeping around, etc. Even the heart and soul of the show, Jim & Pam, both became pretty unlikeable this season after all their contrived marital drama. (Note to Hollywood writers - people outside of Hollywood actually enjoy happy marriages, they're not all embittered and self-absorbed as you seem to be fixated on)
I liked Dwight as a hapless dweeb that was annoying but constantly tormented as Jim. I liked Ryan as the quiet, nerdy intern. And I liked Andy and Erin as Jim/Pam II. (Sorry Plop, you were too handsome and unfunny to ever warm up to)
Anyway, they had a good run. A lot of high moments...Michael burning his foot in bed on the George Foreman grill will always be a classic.