[copperx]

I'm curious about what constitutes a profuse apology. Does it include long explanations? Or does it take into account how the other party was inconvenienced?

I'd love to know this. Are there any great books about Japanese culture?

[t-3]

I'd imagine it's the difference between businesslike sorry-not-sorry stuff like: "We're sorry to inform you that we are not moving ahead with your application", and actually trying to apologize to someone. The not-actually-apologetic stuff is basically just normal parts of polite speech for the culture, actual apology with emotion or intent to make redress or request forgiveness is very different.