I'd like the power to control my own sense of time, It wouldn't actually be able to pause/stop or speed up time, but just effect my own sense of it, allowing me to see and react to things in slow or fast motion. If I ever end up in a fight, I could slow my sense of time in order to react easily to any attacks far before they hit me. If I were bored of something, I can simply speed up my sense of time and it would even help in video games etc. by allowing me to react milliseconds after something happens.