Could you please educate me in the nuances of "I'm sorry"? My girlfriend sometimes says my apologies don't count because of the tone of voice I use when I say "I'm sorry." She said I sound "resentful instead of apologetic." Shouldn't she just accept the apology and not split hairs like this?

--Man In Apology Doghouse

Ideally, your tone of voice in apologizing simply communicates "I'm sorry" and not "I'm sorry you're such a total idiot about this."

Whenever you speak, the emotional packaging -- your tone and attitude -- is an integral part of the message. That's because, as evolutionary psychologist Laith Al-Shawaf and his colleagues explain, one function of human emotions is to act as signals, broadcasting our feelings, perceptions, and intentions. Accordingly, an apology in a snarly package -- words of regret delivered in a resentful tone -- reads not as an apology but as an evasion of responsibility in an apology suit.

For an apology to count for us psychologically -- allow us to let go of our hurt and anger and move on -- it needs to be backed with sincere remorse. This isn't to say you have to throw yourself weeping at a person's feet because you left the toothpaste cap-free for the 500 millionth time. Your tone just needs to translate to a sort of pledge to try to do better -- which suggests that you value the person and the relationship, which allows them to trust you going forward.

But let's say you're snarling "sorry!" because you feel whatever was expected of you (that you fell short of) was ultimately unfair. In that case, it's better to instead say, "I see you're feeling upset" or "hurt" -- "...and I think there's a misunderstanding here that we need to discuss." If things are too heated in the moment, you can ask to talk in a few minutes or an hour or whatever. This tack is sure to have a far better outcome than the classic unapologetic apology -- "I insincerely apologize for the thing you say I did" -- which tends to be met with "I'm so sorry you'll be taking this mildewy army blanket and going out and sleeping on the lawn chair...indefinitely."