As a general rule, say sorry when you make mistake. Apologize for your mistakes. Don't say sorry when you aren't making mistakes.
I figured this out at some point, but I really wish I had figured it out fifteen years earlier.
I would add an exception to the rule: I recall someone around here (I think quoting HPMoR) distinguishing between apology as regret and apology as submission. Some people only hear the latter. The rule does not work with them. They can usually be identified by explicitly demanding apologies or at least angling for them. Someone you have actually wronged probably doesn't want an apology; they either want you to go away, or they want you to suffer.
They can usually be identified by explicitly demanding apologies or at least angling for them.
Grammatically, this sentence means "If you demand apologies, that is a way for you to identify these people", but I think that you meant "They can usually be identified by their habit of explicitly demanding apologies". Passive voice can be tricky.
Do the following things in email tone lower status?: