Spoiler question, do not read if you didn't complete the game at least once!
After reading this answer to another question, I was intrigued by one of the spoilers:
The Railroad will want you to destroy the Minutemen
While I understand that they want to put down the BoS, I was thinking they would want to destroy the Institute to liberate the synth.
In my first playthrough, I got so far I destroyed the BoS for them, but switched to the Institute at that moment, and destroyed thm before I could see that quest.
All along, the Railroad never have qualms about the Minutemen, and the Minutemen are quite neutral, so I don't understand why the Railroad is the only faction to want to put them down.