Exactly what it sounds like
Not every alternate world Twilight went to was a villain's playground. Some were only mildly worse. One was arguably better...
Twilight has been keeping Spike up at night with obsessive writing. One night, Spike's curiosity gets the best of him, and he discovers Twilight has been writing bad shipfiction about herself and her friends. He decides to teach her a lesson.
Nothing sensible can come of this
When Celestia retreats to the starry realm of ascension in order to look upon the past, Luna joins her to discover what it is that is bothering her.
Discord's mom, Eris, shows up during his evening with Fluttershy to see how his evil plans of causing chaos all over Equestria are going.
The Cutie Mark Inspector visits Ponyville to conduct a cutie mark review of the townsfolk. When it transpires that every pony has been interpreting their cutie marks wrong, Ponyville is thrown into chaos.
Celestia is tired of being held above everypony else, like she so "deserves".
Ponyville is experiencing a bad weather week with Dash out of town. When some of the other farmers learn Applejack is planning to date the town's lead weather pegasus, they fear the bad weather will continue and vow to put a stop to it.
A miniature Lyra helps you forget the day's worries.