Have you ever sent a super-important email to someone just to have it go unreplied to for days while you stew in your thoughts? Finally, about a week later, you get a reply that says something like “sorry, I had meetings all week.” Yeah, that is not cool. It’s a jerk move.
If you come across an important email that you cannot fully respond to at that time, just ship off a quick email that reads, “Hey, I got your email, but I will need X days to get you a response because I am in meetings until X.”
Better yet, set an automatic reply that says you are in meetings all week and will reply on a certain day. This is especially important for a manager who gets a lot of emails.
That will save the sender a lot of stress awaiting your delayed response and keeps you from looking like a jerk.