Crazy add-on's for your email account

Hear me out guys, I was facetiming my friend the other day and complained to her briefly about easy it is for people to ignore emails these days ...

and then she told me that she installed an extension on her email that lets her see immediately when someone clicks open her sent emails, aka a tracker for how long someone is possibly ghosting you and for how long!

i got a little freaked, though i hid it well from the friend. i personally feel like having something like that installed would make it more nerve-wracking for me.

what do you guys think? and what are some cool if not less intense add on's or extensions you have for your virtual mailbox?