When I was 8 years old, walking through my childhood neighborhood, my mom told me if I took a small "pup" off an American agave and stuck it in the ground it would grow. I planted one tiny little agave on the hill outside our yard and several years later, long after my folks divorced, the pup had grown into a huge cluster of Agave americana "Variegata". It was heart warming. 

A friend gave me a snippet of a "Creeping Charlie", which I started in water.  Those white tendril roots emerging from the nodes and growing longer and longer were a revelation to what happens out of sight underground - like peeking into the secret world of plants. Next step was observing the cut-off limit to transferring from water to potting soil, as if the plantlet was protesting, "What is this hard dry stuff?  I want my water back!"