I have heard of an experiment that they did at an university. One group screamed and yelled at a plant all the time they came near it. Another group said soft voice words at another identical plant. In 6 months time the one plant that was yelled at died while the other thrived. I have no way to back up that story except I heard it on TV many years ago.
I do believe that some people have a 'green thumb'. I think the plants know they are safe and accept their touching. Sounds weird but I have seen people graft trees and ever one took and thrived while I could never have success. Also my neighbor could cut and plant anything and it grew. He had flowers and plants all over his house from ever where he visited. So who knows?
Stush