If it was loud on Monday it's also loud on Tuesday

I lived in the same rental house (split into 4 apartments) from 2004-2012.  During most of those years, I had a very noisy neighbour either next to me or above me.  She would blast her music most days, and I cannot count the number of times I had to phone and tell her to turn her music down.  I even tried to invite her to come into my apartment to hear what it sounded like on several occasions but she would refuse and always seem incredibly surprised that I could hear it.  DUDE PLEASE I don't just phone random people for kicks and tell them to turn their music down.  Have I ever phoned you when your music wasn't on?  No?  Then I'm obviously hearing your music!

It has always boggled my mind, the music blasting neighbours thing.  If someone calls you on Monday and says "your music is too loud" and you're like "OMG I'm so sorry, I will turn that down immediately", what is a logical volume to set your speakers at on Tuesday?  Hint:  Probably not the volume you had them set at on Monday before your neighbour told you to turn it down.

And yet, this is what noisy neighbours always do.  Brahm and I have a noisy neighbour in our current apartment too, and yesterday his music got so loud that Brahm went and told him to turn the bass down.  He was very apologetic and didn't seem to realize his music was so loud and turned it down to a respectful volume... and then promptly at 6:45 this morning (we don't need an alarm clock) started blasting it again at full volume.

WHY?  This is one of the mysteries of life I just don't understand.  I'm sure it's always a bit embarrassing to be asked to turn your music down... why invite that again, or worse, complaints to the landlord?  You MUST know it's still too loud, because it was too loud yesterday!