What I try to ask is: How does your new thing relate to x, y, and z <prior art>. Because (a) I'm curious, (b) it puts their thing into context, and (c) they should know.
Also, project read-me's should have a prior arts sections. Know and give credit.
(thread)
whenever you tell people you built (or are building) something, and they respond with things like "(did you know) you could do it with this X, Y, and Z thing that already exists...", it's interesting to examine their possible motivations.