Avoiding Date Misinterpretation
That is why you should always make sure to spell out the month. Write May 10, 10 May or something similar instead of 05/10 or 05-10. This makes it clear what date you are referring to.
There are many times that I am not in a position to respond immediately to an E-Mail that I have received. In such a situation, I make sure that I send a short message acknowledging receipt of the E-Mail and inform the sender that I will respond soon. This way, the sender does not have to wonder whether their E-Mail has reached me in the first place or wonder as to why I have not responded to their E-Mail.