Perhaps the most oft-used rule at BookEnds is the 24-hour rule. Receive an email that you’re super excited about? Take 24 hours to feel that excitement, then reply level headed. On the other hand, take 24 hours off the emails that might set you on edge.
Once those 24-hours are done, you’re likely able to deal with the problem more level-headed and logically.
(PS: this applies to more than just work emails).