Shirobako has no bad episodes (I'm not a fan of the first episode, but I see that it was perhaps impossible to do what they did and compose it otherwise). So when I rewatch Shirobako, I rewatch it whole. However, in a number of other series I end focusing on 1 episode that is good, and often it ends being very, very good (such fixation is not new). And I commonly select such super-rewatch episodes from the series that were not to my liking overall.