I think they're all pretty funny, even though we see the themes repeated so many times in virtually every episode. But I must say, the only one that does seem to bug me is Elizabeth. I can totally understand and relate to her being overly nervous given Hyacinth's yammering on about her high quality china. But she goes all hammy and overboard and over-acts (in my opinion). It's much too forced and too exaggerated. It borders on silly and unbelievable compared to how everyone else pretty much just looks irritated, annoyed, uncomfortable and tries to avoid her. In these instances, her portrayals seem much too amateurish and juvenile.
Otherwise, I pretty much enjoy the running gags, even Hyacinth being over the top with her falling into the hedgerows. Liz just seems too fake, if that makes sense (in those scenes).
______________________________________ And I stepped on the ping pong ball!