I not great with estimating sizes, and i often have trouble converting things from feet to meters on the spot. Last session i presented the players a quest to slay a sea monster. They cleverly decided to scout first with a familiar, and i described the creature and its size. I ended up exaggerating the size i bit too much and they've decided to avoid it until they're higher level. So what was supposed to be a simple "monster of the week" type of encounter has now turned into a late game boss fight.
One time I decided to name an enemy faction based on a bad pun. I told the players the name was chosen intentionally, and one of them especially was doing some moderate research to try to figure it out. When I finally played the pun a year later, everyone groaned. It wasn't even a good pun.
The game's premise was "what if the head vampire in the city was basically Trump, and you're all freedom fighters?" The bloodline was called the Publii. It was a setup so I could say something like
spoiler
"We publii can control the city! It will be terrible!"
That is, "Republican control the city! It will be terrible!"
It's really bad. The grammar isn't even quite right.
