wet blanket

(noun) a person who spoils other peoples’ fun by being very boring

Example Sentences:

A: Let’s go to the beach! I want to sit in the sun! It’s been a long winter!
B: I don’t want to get skin cancer.
A: Okay, let’s go get a beer!
B: Beer makes you fat.
A: Do you want to go shopping?
B: I don’t want to spend money.
A: You are such a wet blanket.

Every time Stuart and his friends go out for dinner, he makes them feel bad about eating expensive food because poor people can’t afford to eat it. Stuart is a wet blanket.

Wayne: Let’s go clubbing! I want to get drunk!
Garth: I’d rather stay home and drink milk.
Wayne: You are a wet blanket.

From the Blogs:

Stand to Reason Blog: Wet Blanket Believers

Media:

Similar idioms:

1. buzzkill
2. take a stand on
3. screw around
4. wet behind the ears