When someone needs to learn to fish is when they really want or need to know the answer to their question. It teaches them to research items of interest so the rest of us don't have to read, "Can I turbo my NA?" for the 59692485th time. (hopefully).
When someone asks for an answer about the product you are pushing is when you really want them to know the answer to their question. Your education of them may incite them to buy.
See the difference? Some guy asking why his Z keeps stalling at speed NEEDS to know the answer to his question. If it's not handed to him, he just may go looking for it. But for Sacto, the well-being of his car and driving enjoyment isn't at stake, so if you don't dangle that fish right in front of him after frying it up in some nice, tasty seasoning, you probably won't make that sale.