I might ask a coworker something critical in an email and not hear back in a week. Someone else sends me an email with that coworker copied and he instantly replies butting in his opinion when it wasn't asked.

I send an email as an FYI to document something that happened, doesn't need a follow up. EVERYONE replies with the lulz

Still waiting on the reply for the critical information.

Makes it clear that they are deciding to avoid certain emails.