really? if someone sends me a long message and I respond with a few lines, it's quite difficult to not come across as rude. If you have a four page essay, if

really? if someone sends me a long message and I respond with a few lines, it's quite difficult to not come across as rude. If you have a four page essay, if I am to reject or accept it in a few lines, I'm only addressing a few of your points. How do I respond politely to a four page essay without spending a significant amount of time on it?