Running or playing sports.
Blending in with the crowd.
Doing chores or housework
Elastikyness, to be really flexible and stretchy.
To be able to run really fast.
To be really strong.
To be like invisible... a forcefield would be good too...
Red and kinda yellow too...
A nice homey colour, maybe pink.
Apparently violet is the fastest colour of the rainbow, but black looks cool.