Yeah xD Always full of surprises. Like for example my players were asking "what kind of magic items were stolen" and I hadn't prepared anything because I just meant for them to be used as batteries, so the NPC said it was weird because there were no connections, for example there was a weird magical candle, and the two players who've been playing for a long time immediately went "oh no" and told the others that there's something called a Candle of Invocation which is apparently a really powerful item for traveling between planes, so now that was totally part of the plan all along.

What kind of campaign/party are you DMing?