Speaking as someone from Edinburgh where the locals are notoriously jaded (ask someone that has lived in edi for a few years what festival shows they went to this year): It's more that we _forget_ rather than never knowing.
Asks me what cool things to do nearby on the spot and I'll probably draw a blank. But say what you are doing instead and I'll probably go "oh yeah! That's brilliant! I love thing X".
I do know where good dog walking spots just outside Edinburgh are though, and I'm still regularly discovering more because I'm effectively a tourist ;).