I don't mean to rain on your parade, but we both know that an expert is someone from off-planet with a briefcase.
I'm really sorry to rain on your parade but here are the facts.
I hate to rain on your parade, son, but Anna doesn't want to leave.
"It is to be hoped that it will not rain on our parade."
"I think she didn't want to rain on your parade."
Did he really accuse me of raining on his parade?
"Sorry to rain on your parade, but we buried that idea a couple of months ago."
"He didn't want to rain on your parade," sighed Lucille.
But I'd be careful about raining on his parade real quickly.
I'd prepared myself for the dubious reward of raining on their parade.