Gas and the Winds Blow

Pelples say I'm free, free wherever I go, I could be anywhere, in all directions. I do not have the form, and easy to change the shape. I am a very light material, unappreciated and tend to be hated by others. I walk aimlessly, always follow wherever he goes, if he run then I will come running after him, if he walk slowly, I will with difficult walking slowly to follow the plot. I am not something that has no purpose, but I would strongly influenced by his existence. If he is silent then I will free fall down and can fell everyone underneath. The effect can be very fatal and can lead slander arise. Me and him am not a harmonious spouse and always hand in hand but his presence will make it easy to determine the direction and destination path. Faster he runs then I will be more eager to catch up and make me free from fatal catastrophe, then I will disappear without anyone knows.

Who am I and what Him is, this is a story telling about the gas and the winds blow.