As we all know, we should treat emails with the same patience and crafting time as a normal letter, but sometimes I just catch something right after I send the email. One of those things has been misaddressing someone. Here are a couple scenarios:
Mixed first/last name. For John Smith, instead of writing Dear John, or Dear Mr. Smith, I write Dear Smith.
Mixed Ms with Mr, so instead of Ms. Doe for (Ms.) Casey Doe, I write Mr. Doe.
Misspellings (self explanatory)
So for the first two scenarios, I'm inclined to send a follow-up email that succinctly just says something along the lines of "I noticed I've mixed up blah blah, apologies, coffee hasn't kicked in yet" (which has been true in the few occasions it has happened).
But what are your thoughts on this? Should you just let it pass and hope they don't take insult in it? Or a short acknowledgement and apology is better?
Edit: In US, some people see as inappropriate addressing someone by just last name. It might be because it is what happens when you're just a recruit in the military (it implies you're "lower ranking")