LostSoul
Adventurer
I hate it when the group comes up with a plan, but the DM wants to "add difficulty" so he just starts obstructing the players by saying no. It's often not about "the integrity of the setting" but rather, "I want to make the players work for their success, so, I'll just make this more difficult, just to make it more difficult". I find it so frustrating when DM's do this.
This is precisely why I roll randomly for minor details that may have an effect on the PC's actions. It helps remove any bias on my part. Not completely - I still decide when to roll - but it helps.
I recall an encounter with about 20 cultists and one PC - she stumbled on them in the cellar of a farmhouse and, after failing to con them, they turned hostile. She decided to flee. I wasn't sure if she had closed the cellar door behind her, or if any of the cultists had shut it, so I made a random roll (1-3 closed, 4-6 open). It turned out that no one had shut it, so she escaped.