Messing with people's thoughts using sound

I find it amusing how easy it is to break one's concentration.

I've been experimenting by imbuing a thought and a pattern into sound, when the sound is created, the pattern similar to one's thinking is broken and original thought overwritten with external thought.

I've been messing with mom lately. She's playing games i snip my fingers slowly and increase the speed (causing more careless thinking, concentration on sound instead of game) then when i think it's good enough, i create a louder one followed by silence (Thought:"What now? What am/was i doing?"). The moment she realized that she had been concentrating on sound, she already failed at the game.

Much easier is just saying:"You will fail." causing person to imagine failure and to subconsciously materialize it.
I've said "you will succeed" and that worked, but lot less. Probably i've programmed her to think of failure. Hmmh...

I was also messing with her when she was talking with her sister (originally, i wanted to try breaking thought pattern of her sister instead). I used quiet, high-pitched whistle, concentrating on imbuing the thought of nothingness. It was more effective than i thought. She started lagging, as if parts of thoughts were cut off.

It's fun to mess with people. But i will restrain myself from doing so. Either way, what right do i have to do so?