Rain on someone's parade.
[Idiom] RAIN ON SOMEONE'S PARADE. - Find Out How to Say Someone Spoiled the Fun
Spoil plans.
To "Rain on someone's parade" means to spoil something, such as an event or a plan, usually by bringing bad news or negative attitude. It’s when someone diminishes the enthusiasm or ruins an occasion for others.
Example Sentences
I hate to rain on your parade, but we can't go.
I hate to spoil your plans, but we can't go.
She really rained on his parade with that criticism.
She dampened his excitement with harsh criticism.
They planned a perfect picnic, but the sudden downpour rained on their parade.
The sudden rain ruined their perfectly planned picnic.