The thing is, most of the time we're not trying to be difficult when we write to someone else (although I could be wrong). When misunderstandings take place, it's more about the receiving party taking the meaning differently than intended. We miss the tones and inflections and so we take the words however we want to or based on the mood we're in.
So, how many times have we misunderstood the message? How many times have we received an email that was innocent or benign, put a negative spin on it, and taken it as an attack? How many times have we ripped off a scathing response, one that anyone would KNOW was negative, only to find out later that the original message was not intended to be antagonistic?
We need to give email writers the benefit of the doubt. Unless we know the person at the other end is out to hurt us (and has proven it in others ways besides email), we need not jump to the negative.
We have several choices of how to take an email's meaning. Let's choose to put a positive spin on them and give the writers the benefit of the doubt until they prove otherwise.