Every now and then (especially when I’m feeling tired or absentmindedówhich is unfortunately almost always nowadays), when someone addresses me with a greeting or other phrase that is customarily given in a particular social context, I goof up with my obligatory reply.
Sometimes the slip-ups are reasonable, such as if I’m going to bed at a time when another family member is just starting the day, who tells me “goodnight”, and I say the same thing back; or if I greet someone who has woken up past noon with “good morning”. Other times my response is completely incompatible given the scenario. For instance, after dinner a couple of days ago I was thanked for putting my dish away, and I almost said “goodnight” in return. Oftentimes I realize that I’m mincing my words before I’ve finished the phrase (or, as in the above case, even started it), and correct myself, but there are also cases in which I do not even realize I am saying the wrong thing until I am finished, and either reflect on what I just said or have my mistake pointed out to me by someone else.
A lot of the time it seems like my brain is operating my mouth on autopilot, and stuck in the mode when my reply should be the same words the first person said to me (such as “goodbye” or “good morning”); there have been times when someone has said “happy birthday” to me, and I say “happy birthday” back.

And don’t get me started with all the times I’ve said “thank you” instead of “you’re welcome”, and vice versa.
