I know this is only tangentially related, but recalling messages is horrible. I hate that so many services will allow people to send me a message, give me a notification with a preview, but then the message gets edited or deleted. If you drop a letter in a physical mailbox, or slide a paper underneath the door, you cannot get it back either. This whole philosophy of 'we allow destruction of messages in a shared chat' needs to stop. The moment things are being sent, both sides are co-owner of that message. Not being able to recall messages is a good thing.

I'll settle for a brief edit (not retraction!) window after sending though, say 5 minutes tops.

Edit (I realize the irony): banks of course won't give a hoot about the receiver, the power dynamic is inherently not equal.