Our modern world is all about instant gratification, immediate turn arounds and prompt responses – even at midnight on a Saturday. To differentiate you have two options – respond faster than anyone else or show patience and timing.
In reality, how many messages require a 5 minute responses? Think about how peaceful it is to the sender to hit send and forget on things that he doesn’t need to hear about until two days from now. There’s a delay send feature in Outlook, why isn’t there a delay reply responses option?