Yes, you should be using exclamation points in your emails — here’s why
Exclamation point is effective in conveying facial expressions and physical gestures when communicating in cyber space

Something curious happens every time you open an email.
Whatever enthusiasm the sender meant to convey is immediately taken down a notch — so that, if it’s an email from your boss communicating her approval on a project, it might sound to you more like a “meh.”
That’s according to Jocelyn K. Glei, author of the new book “Unsubscribe: How to Kill Email Anxiety, Avoid Distractions, and Get Real Work Done.” Glei argues that there’s one sure way to fight this phenomenon: Sound more excited when you write an email. Specifically, don’t be afraid to use exclamation points (really!) in professional email exchanges.
In “Unsubscribe,” Glei mentions the “negativity bias,” described by psychologist Daniel Goleman in a 2013 LinkedIn post:
“[T]here is an actual negativity bias in email where senders think that a message was positive, but that’s because they assume all the other cues were clearly received. It’s an unconscious assumption.
“Receivers think that positive email was more neutral. When the sender thinks it’s neutral, receivers tend to think it’s more negative. In other words, there is a general negativity skew to email.”