I have some coworkers and customers that send all of their e-mails with read receipts requested. Whenever I view one of these emails in Gmail and then try to leave, it asks me if I want to send a read receipt or not. I always click "No", but even if I view that message at a later date (such as trying to find an old email on a particular topic), Gmail will continue to nag me about sending read receipts.
Is there any way to tell Gmail that I never, ever, under any circumstance, never want to send a read receipt? This drives me absolutely insane. I must spend several hours over the course of the year just dismissing read receipt dialogs.