There is a difference between nice and overly nice.
And I'm not talking about the time it takes you to be nice, but the time it takes others to process your niceness.
For instance, burying the lede on what the email is for in order to say "I hope this email finds you well". Use that space to get to the point so that the person on your receiving end can process the email quickly. If it is a request, say please but nothing beyond that.