just those snippets of conversations that you're not involved in that you overhear and its not even louder than the rest of their conversation it just stands out to you. I feel like that deserves an artsy vaguely pretentious word like on par with "wanderlust" a fancy pretty sounding word like that.
I don't know about a single word, but the correct phrase would be "selective hearing".
It's when your auditory system hears all the sounds and noise in the surrounding environment but only certain parts of the information are processed by the brain.
Similar to how when you learn about something and then suddenly see it everywhere (a type of bird for instance) it's because your brain recognizes it and latches onto that. There's so much information in the world - too much for your brain to process all of it - so your brain has to be selective and decide which information for you to notice.
Every time you learn something, it creates a link in your brain. When you learn it a second time, that link is strengthened. These "brain links" make certain phrases or knowledge familiar and determine what stands out to you out of all the information your brain has to process.
Is that what you were asking?
EDIT: Selective hearing is also called 'Selective Auditory Attention', which sounds a bit more pretentious/fancy like you asked for.