Short and sweet.
We were playing a long term Spelljammer campaign. Our adventuring got us hired to clear out some asteroid farm that was infested with some burrowing hive creatures that had captured some man's child.
We land on the asteroid, find the hole the creatures were nesting, and begin climbing down. I remember our wizard PC remarking, "Tunnels! But I memorized fireball today!" Our DM was telling us in vivid term how fragile the walls were, any loud noises or could cause the tunnels to collapse upon us. We carefully cast silence whenever we get into a combat to keep the noise levels from being a factor.
We crawl deeper and deeper, until we finally end up in a chamber so large our light sources could barely see the opposite walls, but we were told that in this room our dwarf could easily tell that the ceiling could easily come crashing down upon our heads if we made the slightest noise. Across the room, stirred the child, all webbed up in a cocoon.
Suddenly, above us creatures began stirring out of their holes in the ceiling.
Before any of us could react, our intrepid wizard panics. She casts fireball at the ceiling.
We were all stunned into silence. The DM was likewise, but quickly responded nonchalantly, "Are you sure you want to cast fireball here?"
"Yeah, you said there were many of them right above, the room is large enough that the fireball won't envelope us [remember how 2nd ed fireballs filled a volume?-- ed.]. I've been waiting to cast this spell all day, those tunnels prevented me from casting it and I can finally cast it! I cast it!"
Our group all died in the cave collapse. The child did too.
The players were in serious outrage for many years after that. We look back now and laugh.