It is pretty funny until s7 or s8. From there began the downfall. The last few seasons lacked motivation. They just made it to milk it. The actors couldn't make it to every episodes so they just managed with whomever was available.

What I hate the most is that how the characters don't act based on what happened in the earlier episodes. For eg, there's one episode where a Doctor says Luke is actually kind of a genius, but he continues to do pretty stupid things until last season. Didn't like what happened to the other kids as well. The ending was way too rushed. It was neither funny nor touching.

But there's several funny moments throughout the series. Watch it if you want to pass your time.