Mine is my super-duper green thumb and its ability to make things grow.
No, I just cannot stop the power of my green thumb to make things grow...even when I'm not trying to grow anything!
Case in point: French Pussy Willows. Here they are in a vase--an early spring ritual of clipping branches from a huge tree and setting them in water so their catkins, all fuzzy and cute, will come out inside the house to remind you that warm weather is coming and with it flowers and blooming trees and twittering birds and such.
But what does my green thumb do? It makes the silly sticks take root! Now I have a half dozen potential French Pussy Willow trees to plant somewhere. My green thumb never fails.