Thoughts are seeds for every action. A cluttered mind produces actions which results in chaos outside. Imagine thoughts being a wire, so every time we think about someone the wire of our thoughts gets connected to them. At such moments what we think about we download that energy.
In case of a radio frequency, there are all channels in the air but only the one’s which we tune to start playing. Thinking of mind as a radio, which thoughts would I want to listen to if thoughts were music?
But what is the proof that if I am thinking about person X then my mind gets tuned in to that frequency ? So if person X is generally angry I have high chances of feeling the same or feeling low whenever I think about that person ?
The famous Hundredth monkey syndrome experiment explains how an idea enters from one group to another through unknown means. In other words, transfer of ideas from one mind to the other mind happened through means which the experimenters were unable to understand.
Nevertheless, the best way to observe the above claim is self experimentation. We all can choose anytime to observe how our thoughts determine our feelings. Since most of the time we are either thinking about people or situations, taking a break any minute we can simply check that how feeling shifts from low to high with a shift in a single thought.