The previous episode ended with Ted being left at the altar. This one can be regarded as the sequel, illustrating the aftermath and the consequences the gang necessarily has to deal with, before the "Stella"-chapter can finally be closed. How can you make something like that fun?
Answer: Flashbacks!
This is done quite well. Barney's and Lily's stories are funny, and we learn more about Robin's past. More precisely, about her father issues, which have been first mentioned in S01E14. It's not all great continuity, though. In S01E20, we learned Robin used to play field hockey. Now we see her play "actual" hockey as a teenager. So much for "I never played any teams sports" (S01E06)...
Not the most enjoyable episode, but we needed to get that stuff out of the way. And for the most part, cast and writers make the best out of it.
Answer: Flashbacks!
This is done quite well. Barney's and Lily's stories are funny, and we learn more about Robin's past. More precisely, about her father issues, which have been first mentioned in S01E14. It's not all great continuity, though. In S01E20, we learned Robin used to play field hockey. Now we see her play "actual" hockey as a teenager. So much for "I never played any teams sports" (S01E06)...
Not the most enjoyable episode, but we needed to get that stuff out of the way. And for the most part, cast and writers make the best out of it.