My favorite is the knobs where some of them you can grab and rotate like they are physical but other ones only react to the vertical position of the cursor so you feel like a crazy person trying to use them
If you're into skeumorphism, you'll love it. I put a lot of care into how the buttons and other elements work and interact with each other.
(It's a free little dog journaling app I created with my partner to help us cope with losing our dog)
A 30-second demo video on the landing page would be absolutely fine, or half a dozen large screenshots showing the features.
It was founder therapy first and foremost (and an exercise in serious play).