If I sent you send me an email, and I hit "reply", it sends the reply to you.
If I don't hear back, and I send a followup by hitting "reply" to my last email, it sends that followup to me not to you.
This is undoubtedly because Apple Mail semantics is "reply means use the 'from' address as the 'to' address." This is not how GMail works and not how any other mail client works, that I have used.
Is there an option somewhere to get Apple Mail to set the 'to' address in replies to be "the other person who isn't me"?
Edited to clarify: this is on MacOS Mojave 10.14.3