Teleportation
Specifically, without an impact on the ambient in between teleports, so I could do it quietly
Then, I couldn't be late anymore
Or still get late, but throw the excuse of "being there on time, but was on the bathroom" (can quick teleport my stuff and drop them there as a proposital signal)
And kill all the wasted time and money in transport (no more almost 2h to reach from home to college)
Also, tripping to everywhere easily
I wouldn't need even a hotel, since I could teleport back home and sleep on my own bed, and forgetting stuff in home wouldn't be a problem anymore too
Also following kenx idea, would be fun to practice the ability to expand the teleportation distance and accuracy little by little
Maybe even reach to the point of be able to teleport between planets, realities, time travel (or, in this case, time teleport) and wherever I find fun to go
But probably I would just don't do anything to much gaudy and that draw attention, or I could end like the Ajin in the government hands (becoming a lab testing subject would be painful and sad)