Hmmm....for me is easy to say the ones I don't like!.....lets start with S2E6...that's the one with his parents ...horrible people , S3E7...OF COURSE!! this one don't need to be mention beyond the number , S4E4 that one is a very low point in their relations , and S4E1 is not one of my favourites, just because Edith is there TOO MUCH!
Lol I know what you mean - also the day they are perfectly happy is when the show can't really do much more so I'd rather have some sad bits too. We've got fanfic for romance!