Some folks I knew in Marble Falls, TX that grew greenhouse tomatoes for grocery stores would go through the greenhouses with a chainsaw fired up, threatening to kill the plants. They swore it worked to really up the tomato yields.
a chainsaw might be a little over the top !!
There is a book I read ,way back when , called : "The Secret Life of Plants "
It said that plants could read your intent be it good , or bad and wish them harm, and that they would respond accordingly .
For those who complain of having a "Black Thumb" , it still makes for an interesting read , and is quite thought provoking in horticulture .
It is a book sorta like Dale Carnagie's book , "The Power of Postive Thinking ", and it states that plants can respond to our thought processes and plants respond .
Plants are like people in that they too can become complacient; but if you shock them a little , they respond with the need to propogate .
I'm not sure I would have believed it myself ,had I not gotten the positive response , on several occassions ....YMMV