I stufferd a store in for my players to shop (Foundry) because it had been a while, and just grabbed a pre-built one and tossed it in…

they spent the night planning and implementing a massive heist because one item cost too much for them to afford and they wanted it… I had NOTHING for this (half the players beliefs on the shopkeeper, how they worked and how they could be robbed was based on some crappy random generated name and they had made “assumptions”…)

Found out later they thought I planned it all