I have avoided watching this show ever since the finale aired, it soured the entire show for me. But recently my roommate started watching it, and I occasionally watch some episodes with him. I have to say that the show has maintained its charm. From season 1 to season 6 it is absolutely terrific and the show should have ended there IMO.
After that we had season 7, which I didn't like but it was watchable. Then came season 8, which is absolutely the worst season and really destroyed the goodwill. Then season 9 had an interesting idea but wasted it with repetitive and unfunny episodes.
The final bomb came with the finale, which made it hard to hear the theme song for me. It has taken more than 3.5 years after than shitty finale for me to return to what I otherwise still consider to be my favourite sitcom and one of my favourite shows.