Scale is something that has always fascinated me.
Specifically, I love the idea of seeing two things at dramatically different sizes interacting with each other. Normal characters and Giants, Wee Folk characters and a normally sized forest environment, or Giant Robots versus Kaiju in traditionally sized city. This sort of thing has always intrigued me.
Of these ideas, being Small and dealing with a normal size world is definitely my favorite situation. Be it Honey I Shrunk The Kids, The Micronauts, or The Littles, the terrain and gear of such a narrative is very inspiring and exciting to me as both a GM and a player.
I have only gotten to run this sort of things a few dozen times at most over the past 40+ years and every time it's been a blast. It is usually in a Fantasy context, with the PCs playing Faeries of some sort, including a short stint with my Smurfs RPG variant on the wonderful Faery's Tale Deluxe.
I look forward to doing it again in the (hopefully) not too distant future. There is a Japanese TRPG called, 'Twilight Comes To Autumn Country' that is just begging for a Barking Alien take on its world of miniature, melancholy setting of fading magic.
Twilight Comes to Autumn Country
Beware my players, for soon you might find yourselves really Small.
Entry 7 - Small