Depends. If it's within your own org, there are often ways to server-side remove the email from everyone's account. I've seen it happen with an Outlook/exchange

Depends. If it's within your own org, there are often ways to server-side remove the email from everyone's account. I've seen it happen with an Outlook/exchange setup before. Outlook also offers the ability to draw attention to your email by sending out a "The sender of this email would like to recall it. Please click okay when you're done reading whatever they sent and want to delete it."