To start with, I think that whoever invented email read-reciepts (and, in case they're different people - whoever came up with the idea) should be stripped of their skins and then dipped in lye or something likely to cause even more discomfort. I fucking
HATE email read receipt requests.
If you're one of those people that thinks setting a read receipt request on emails is a good idea, I'll clue you in: it's not. It makes me and most people fucking hate you. If I'm working with an email client that gives me the option not to send a reply, I will never fucky hit yes on the "permit read-response" pop-up. The only way I'm ever hitting "yes" is if my email client ever offers the option to send a custom reply. If it does, you won't like that edited response.
To me, the read receipt request is just snotty. When I see one, the way I take it as "this fucker doesn't trust me to read his emails." Worse, I take it as a really passive-aggressive and cowardly way to convey that distrust.
I live on trust. If I get the impression you don't trust me - especially if I've done nothing to earn that distrust, then I really want nothing to do with you. Simply put, I can't trust someone that (obviously) doesn't trust me. When I see that read receipt request, it does nothing but create contempt in me for you.
The only thing that makes it tolerable is that most of the people using them seem to be fairly clueless - either technically or socially. I get that they may not mean it the way I interpret it. Because I'm a fairly direct person, I'll usually let the sender know, "I don't appreciate this" and tell them why.
If they persist in their cute little habit, that's when they can expect me to stop replying to their emails because I've set up a rule in my mail client to "auto-sort" their communications into a "never gonna read this" folder.