I think it would be cool to be able to control how fast I travel through time. Every one else could be going at normal, but I would be going 500,000 time faster, so it would seem like I had put the world on pause, and I could move through it like I would normally. Sort of like that scene in Matrix one where Morpheus says "freeze it!" during the program. But, to every one else it would just seem like I was moving incredibly fast. (if they could even see me) Or I could slow myself down just a bit for cool fight scenes.